Auxiliaries formed the standing non-citizen corps of the Roman army

Roman army

The Roman army is the generic term for the terrestrial armed forces deployed by the kingdom of Rome , the Roman Republic , the Roman Empire and its successor, the Byzantine empire...

 of the Principate

Principate

The Principate is the first period of the Roman Empire, extending from the beginning of the reign of Caesar Augustus to the Crisis of the Third Century, after which it was replaced with the Dominate. The Principate is characterized by a concerted effort on the part of the Emperors to preserve the...

 (30 BC–284 AD), alongside the citizen legions

Roman legion

A Roman legion normally indicates the basic ancient Roman army unit recruited specifically from Roman citizens. The organization of legions varied greatly over time but they were typically composed of perhaps 5,000 soldiers, divided into maniples and later into "cohorts"...

. By the 2nd century, the auxilia contained the same number of infantry as the legions and in addition provided almost all of the Roman army's cavalry

Roman cavalry

Roman cavalry refers to the horse mounted forces of the Roman army through the many centuries of its existence.- Early cavalry Roman cavalry (Latin: equites Romani) refers to the horse mounted forces of the Roman army through the many centuries of its existence.- Early cavalry Roman cavalry...

 and more specialised troops (especially light cavalry

Light cavalry

Light cavalry refers to lightly armed and lightly armored troops mounted on horses, as opposed to heavy cavalry, where the riders are heavily armored...

 and archers). The auxilia thus represented three-fifths of Rome's regular land forces at that time. Like their legionary counterparts, auxiliary recruits were mostly volunteers, not conscripts.

Auxiliary troops were mainly recruited from the peregrini

Peregrinus (Roman)

Peregrinus was the term used during the early Roman empire, from 30 BC to 212 AD, to denote a free provincial subject of the Empire who was not a Roman citizen. Peregrini constituted the vast majority of the Empire's inhabitants in the 1st and 2nd centuries AD...

, i.e. free provincial subjects of the Roman Empire

Roman Empire

The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

 who did not hold Roman citizenship

Roman citizenship

Citizenship in ancient Rome was a privileged political and legal status afforded to certain free-born individuals with respect to laws, property, and governance....

 and constituted the vast majority of the empire's population in the 1st and 2nd centuries (ca. 90% in the early 1st century). Auxiliaries also included some Roman citizens and probably barbarian

Barbarian

Barbarian and savage are terms used to refer to a person who is perceived to be uncivilized. The word is often used either in a general reference to a member of a nation or ethnos, typically a tribal society as seen by an urban civilization either viewed as inferior, or admired as a noble savage...

s (barbari, as the Romans called peoples located outside the Empire's borders). This was in contrast to the legions, which only admitted Roman citizens

Roman citizenship

Citizenship in ancient Rome was a privileged political and legal status afforded to certain free-born individuals with respect to laws, property, and governance....

.

The auxilia developed from the varied contingents of non-Italian troops, especially cavalry, that the Roman Republic

Roman Republic

The Roman Republic was the period of the ancient Roman civilization where the government operated as a republic. It began with the overthrow of the Roman monarchy, traditionally dated around 508 BC, and its replacement by a government headed by two consuls, elected annually by the citizens and...

 used in increasing numbers to support its legions after 200 BC. The Julio-Claudian

Julio-Claudian Dynasty

The Julio-Claudian dynasty normally refers to the first five Roman Emperors: Augustus, Tiberius, Caligula , Claudius, and Nero, or the family to which they belonged; they ruled the Roman Empire from its formation, in the second half of the 1st century BC, until AD 68, when the last of the line,...

 period (30 BC–68 AD) saw the transformation of these motley temporary levies into a standing corps of regiments with standardised structure, equipment and conditions of service. By the end of this period, there were no significant differences between legionaries and most auxiliaries in terms of training, or thus combat capability.

Auxiliary regiments were often stationed in provinces other than the province in which they were originally raised, both for reasons of imperial security and to foster the process of Romanisation and integration of the provinces. The regimental names of many auxiliary units persisted into the 4th century, but by then the units in question were different in size, structure, and quality from their predecessors.

Background: Roman Republic (to 30 BC)

The mainstay of the Roman republic's war machine was the manipular

Maniple (military unit)

Maniple was a tactical unit of the Roman legion adopted from the Samnites during the Samnite Wars . It was also the name of the military insignia carried by such unit....

 legion

Roman legion

A Roman legion normally indicates the basic ancient Roman army unit recruited specifically from Roman citizens. The organization of legions varied greatly over time but they were typically composed of perhaps 5,000 soldiers, divided into maniples and later into "cohorts"...

, a heavy infantry

Heavy infantry

Heavy infantry refers to heavily armed and armoured ground troops, as opposed to medium or light infantry, in which the warriors are relatively lightly armoured. As modern infantry troops usually define their subgroups differently , 'heavy infantry' almost always is used to describe pre-gunpowder...

 unit suitable for close-quarter engagements on more or less any terrain, which was probably adopted sometime during the Samnite Wars

Samnite Wars

The First, Second, and Third Samnite Wars, between the early Roman Republic and the tribes of Samnium, extended over half a century, involving almost all the states of Italy, and ended in Roman domination of the Samnites...

 (343–290 BC). Despite its formidable strength, the legion had a number of deficiencies, especially a lack of cavalry. Around 200 BC, a legion of 4,200 infantry had a cavalry arm of only 300 horse (just 7% of the total force). This was because the class of citizens who could afford to pay for their own horse and equipment – the equestrian order

Equestrian (Roman)

The Roman equestrian order constituted the lower of the two aristocratic classes of ancient Rome, ranking below the patricians , a hereditary caste that monopolised political power during the regal era and during the early Republic . A member of the equestrian order was known as an eques...

, the second rank in Roman society, after the senatorial order

Roman Senate

The Senate of the Roman Republic was a political institution in the ancient Roman Republic, however, it was not an elected body, but one whose members were appointed by the consuls, and later by the censors. After a magistrate served his term in office, it usually was followed with automatic...

 – was relatively small. In addition the legion lacked missile forces such as slingers and archers. Until 200 BC, the bulk of a Roman army's cavalry was provided by Rome's regular Italian allies (socii

Roman military confederation

The socii were the autonomous tribes and city-states of the Italian Peninsula in permanent military alliance with the Roman Republic until the Social War of 91–88 BC. After this conflict, all Rome's peninsular Italian allies were awarded Roman citizenship and their territories incorporated in the...

), commonly known as the "Latin" allies, which made up the Roman military confederation

Roman military confederation

The socii were the autonomous tribes and city-states of the Italian Peninsula in permanent military alliance with the Roman Republic until the Social War of 91–88 BC. After this conflict, all Rome's peninsular Italian allies were awarded Roman citizenship and their territories incorporated in the...

. This was Rome's defence system until the Social War of 91–88 BC. The Italian forces were organised into alae (literally: "wings", because they were generally posted on the flanks of the Roman line of battle). An allied ala, commanded by 3 Roman praefecti sociorum, was similar or slightly larger in infantry size (4–5,000 men) to a legion, but contained a more substantial cavalry contingent: 900 horse, three times the legionary contingent. Since a pre-Social War consular

Roman consul

A consul served in the highest elected political office of the Roman Republic.Each year, two consuls were elected together, to serve for a one-year term. Each consul was given veto power over his colleague and the officials would alternate each month...

 army always contained an equal number of legions and alae, 75% of its cavalry was provided by the Latin allies. The overall cavalry element, ca. 12% of the total force (2,400 out of a normal consular army of approximately 20,000 total effectives), was greater than in most peninsular Italian forces, but well below the overall 21% cavalry component that was typical of the Principate army (80,000 cavalry out of 380,000 total effectives in early the 2nd century).

The Roman/Latin cavalry was sufficient while Rome was in conflict with other states in the mountainous Italian peninsula, which also disposed of limited cavalry resources. But as Rome was confronted by external enemies that deployed far more powerful cavalry elements, such as the Gauls

Gauls

The Gauls were a Celtic people living in Gaul, the region roughly corresponding to what is now France, Belgium, Switzerland and Northern Italy, from the Iron Age through the Roman period. They mostly spoke the Continental Celtic language called Gaulish....

 and the Carthaginians, the Roman deficiency in cavalry numbers could be a serious liability, which in the Second Punic War

Second Punic War

The Second Punic War, also referred to as The Hannibalic War and The War Against Hannibal, lasted from 218 to 201 BC and involved combatants in the western and eastern Mediterranean. This was the second major war between Carthage and the Roman Republic, with the participation of the Berbers on...

 (218–202 BC) resulted in crushing defeats. Hannibal's major victories at the Trebia

Battle of the Trebia

The Battle of the Trebia was the first major battle of the Second Punic War, fought between the Carthaginian forces of Hannibal and the Roman Republic in December of 218 BC, on or around the winter solstice...

 and at Cannae

Battle of Cannae

The Battle of Cannae was a major battle of the Second Punic War, which took place on August 2, 216 BC near the town of Cannae in Apulia in southeast Italy. The army of Carthage under Hannibal decisively defeated a numerically superior army of the Roman Republic under command of the consuls Lucius...

, were owed to his Spanish and Gallic heavy cavalry, which far outnumbered the Roman and Latin levies, and to his Numidia

Numidia

Numidia was an ancient Berber kingdom in part of present-day Eastern Algeria and Western Tunisia in North Africa. It is known today as the Chawi-land, the land of the Chawi people , the direct descendants of the historical Numidians or the Massyles The kingdom began as a sovereign state and later...

ns, light, fast cavalry which the Romans wholly lacked. The decisive Roman victory at Zama

Battle of Zama

The Battle of Zama, fought around October 19, 202 BC, marked the final and decisive end of the Second Punic War. A Roman army led by Publius Cornelius Scipio Africanus defeated a Carthaginian force led by the legendary commander Hannibal...

 in 202 BC, which ended the war, owed much to the Numidian cavalry

Numidian cavalry

Numidian cavalry was a type of light cavalry developed by the Numidians, most notably used by Hannibal during the Second Punic War. They were described by the Roman historian Livy as "by far the best horsemen in Africa."...

 provided by king Massinissa

Masinissa

Masinissa — also spelled Massinissa and Massena — was the first King of Numidia, an ancient North African nation of ancient Libyan tribes. As a successful general, Masinissa fought in the Second Punic War , first against the Romans as an ally of Carthage an later switching sides when he saw which...

, which outnumbered the Roman/Latin cavalry fielded by 2 to 1. From then, Roman armies were always accompanied by large numbers of non-Italian cavalry: Numidian light cavalry and, later, Gallic heavy cavalry. For example, Caesar relied heavily on Gallic and German cavalry for his Conquest of Gaul

Gallic Wars

The Gallic Wars were a series of military campaigns waged by the Roman proconsul Julius Caesar against several Gallic tribes. They lasted from 58 BC to 51 BC. The Gallic Wars culminated in the decisive Battle of Alesia in 52 BC, in which a complete Roman victory resulted in the expansion of the...

 (58–51 BC).

As the role of native cavalry grew, that of Roman/Latin cavalry diminished. In the early 1st century BC, Roman cavalry was phased out altogether. After the Social War, the socii were all granted Roman citizenship, the Latin alae abolished, and the socii recruited into the legions. Furthermore, Roman equestrians were no longer required to perform cavalry service after this time. The late Republican legion was thus probably bereft of cavalry (a tiny cavalry force of 120 men was probably added back to the legion under Augustus

Augustus

Augustus ;23 September 63 BC – 19 August AD 14) is considered the first emperor of the Roman Empire, which he ruled alone from 27 BC until his death in 14 AD.The dates of his rule are contemporary dates; Augustus lived under two calendars, the Roman Republican until 45 BC, and the Julian...

).

By the outbreak of the Second Punic War, the Romans were remedying the legion's other deficiencies by using non-Italian specialised troops. Livy reports Hiero

Hiero II of Syracuse

Hieron II , king of Syracuse from 270 to 215 BC, was the illegitimate son of a Syracusan noble, Hierocles, who claimed descent from Gelon. He was a former general of Pyrrhus of Epirus and an important figure of the First Punic War....

 of Syracuse offering to supply Rome with archers and slingers in 217 BC. From 200 BC onwards, specialist troops were hired as mercenaries

Mercenary

A mercenary, is a person who takes part in an armed conflict based on the promise of material compensation rather than having a direct interest in, or a legal obligation to, the conflict itself. A non-conscript professional member of a regular army is not considered to be a mercenary although he...

 on a regular basis: sagittarii

Sagittarii

Sagittarii Sagitarii is the latin term for archers. The term sagittariorum in the title of an infantry or cavalry unit indicated a specialized archer regiment. Regular auxiliary units of foot and horse archers appeared in the Roman army during the early empire...

(archers) from Crete

Crete

Crete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...

, and funditores (slingers

Sling (weapon)

A sling is a projectile weapon typically used to throw a blunt projectile such as a stone or lead "sling-bullet". It is also known as the shepherd's sling....

) from the Balearic Isles

Balearic Islands

The Balearic Islands are an archipelago of Spain in the western Mediterranean Sea, near the eastern coast of the Iberian Peninsula.The four largest islands are: Majorca, Minorca, Ibiza and Formentera. The archipelago forms an autonomous community and a province of Spain with Palma as the capital...

 almost always accompanied Roman legions in campaigns all over the Mediterranean.

The main other sources of non-Italian troops in the late Republic were subject provincials, allied cities and Rome's amici (satellite kings). During the late Republic, non-Italian units were led by their own native chiefs, and their internal organisation was left to their own commanders. The units varied widely in dress, equipment, and weapons. They were normally raised for specific campaigns and often disbanded soon afterwards, in a similar manner to the earlier socii militia legions.

Foundation of the auxilia under Augustus (30 BC–14 AD)

It appears that not all indigenous units were disbanded at the end of the civil war period (31 BC). Some of the more experienced units were kept in being to complement the legions, and became the core of the standing auxiliary forces that developed in the Julio-Claudian period. During the early rule of Augustus (27 BC onwards), the corps of regular auxilia was created. It was clearly inspired by the Latin forces of the pre-Social War Republic, as a corps of non-citizen troops parallel to the legions. But there were fundamental differences, the same as between Republican and Augustan legions. The Latin forces of the Republic were made up of part-time conscripts in units that would be raised and disbanded for and after particular campaigns. The Augustan auxilia were mainly volunteer professionals serving in permanent units.

The unit structure of the auxilia also differed from the Latin alae, which were like legions with a larger cavalry arm. Augustus however organised the auxilia into regiments the size of cohorts

Cohort (military unit)

A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

 (a tenth the size of legions), due to the much greater flexibility of the smaller unit size. Further, the regiments were of three types: ala (cavalry), cohors (peditata)

Cohort (military unit)

A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

(infantry) and cohors equitata (mixed cavalry/infantry).

The evidence for the size of the Augustus' new units is not clearcut, with our most precise evidence dating to the 2nd century, by which time the unit strengths may have changed. Cohortes were likely modelled on legionary cohorts i.e. six centuriae of about 80 men each (total about 480 men). Alae were divided into turma

Turma

A turma was a cavalry squadron in the Roman army of the Republic and Empire. In the Byzantine Empire, it became applied to the larger, regiment-sized military-cum-administrative divisions of a thema....

e (squadrons) of 30 (or 32) men, each under a decurio

Decurio

Decurio was an official title in Ancient Rome, used in various connections:# A member of the senatorial order in the Italian towns under the administration of Rome, and later in provincial towns organized on the Italian model . The number of decuriones varied in different towns, but was usually 100...

(literally: "leader of ten"). This title which derives from the old Roman cavalry of the pre-Social War republic, in which each turma was under the command of three decuriones). Cohortes equitatae were simply infantry cohortes with a cavalry contingent of four turmae added.

Auxiliary regiments were now led by one praefectus (prefect), who could be either a native nobleman, who would probably be granted Roman citizenship for the purpose (e.g. the famous German war leader Arminius

Arminius

Arminius , also known as Armin or Hermann was a chieftain of the Germanic Cherusci who defeated a Roman army in the Battle of the Teutoburg Forest...

 gained Roman citizenship probably by serving as an auxiliary prefect before turning against Rome); or a Roman, either of equestrian

Equestrian (Roman)

The Roman equestrian order constituted the lower of the two aristocratic classes of ancient Rome, ranking below the patricians , a hereditary caste that monopolised political power during the regal era and during the early Republic . A member of the equestrian order was known as an eques...

 rank, or a senior centurion

Centurion

A centurion was a professional officer of the Roman army .Centurion may also refer to:-Military:* Centurion tank, British battle tank* HMS Centurion, name of several ships and a shore base of the British Royal Navy...

.

At the start of Augustus' sole rule (30 BC), the original core auxiliary units in the West were composed of warlike tribesmen from the Gallic provinces (especially Gallia Belgica

Gallia Belgica

Gallia Belgica was a Roman province located in what is now the southern part of the Netherlands, Belgium, Luxembourg, northeastern France, and western Germany. The indigenous population of Gallia Belgica, the Belgae, consisted of a mixture of Celtic and Germanic tribes...

, which then included the regions later separated to form the provinces Germania Inferior

Germania Inferior

Germania Inferior was a Roman province located on the left bank of the Rhine, in today's Luxembourg, southern Netherlands, parts of Belgium, and North Rhine-Westphalia left of the Rhine....

 and Germania Superior

Germania Superior

Germania Superior , so called for the reason that it lay upstream of Germania Inferior, was a province of the Roman Empire. It comprised an area of western Switzerland, the French Jura and Alsace regions, and southwestern Germany...

), and from the Illyrian provinces (Dalmatia

Dalmatia

Dalmatia is a historical region on the eastern coast of the Adriatic Sea. It stretches from the island of Rab in the northwest to the Bay of Kotor in the southeast. The hinterland, the Dalmatian Zagora, ranges from fifty kilometers in width in the north to just a few kilometers in the south....

 and Illyricum

Illyricum (Roman province)

The Roman province of Illyricum or Illyris Romana or Illyris Barbara or Illyria Barbara replaced most of the region of Illyria. It stretched from the Drilon river in modern north Albania to Istria in the west and to the Sava river in the north. Salona functioned as its capital...

). By 19 BC, the Cantabrian and Asturian Wars

Cantabrian Wars

The Cantabrian Wars occurred during the Roman conquest of the modern provinces of Cantabria, Asturias and León, against the Asturs and the Cantabri. They were the final stage of the conquest of Hispania.-Antecedents:...

 were concluded, leading to the annexation of northern Hispania

Hispania

Another theory holds that the name derives from Ezpanna, the Basque word for "border" or "edge", thus meaning the farthest area or place. Isidore of Sevilla considered Hispania derived from Hispalis....

 and Lusitania

Lusitania

Lusitania or Hispania Lusitania was an ancient Roman province including approximately all of modern Portugal south of the Douro river and part of modern Spain . It was named after the Lusitani or Lusitanian people...

. Judging by the names of attested auxiliary regiments, these parts of the Iberian peninsula soon became a major source of recruits. Then the Danubian regions were annexed: Raetia

Raetia

Raetia was a province of the Roman Empire, named after the Rhaetian people. It was bounded on the west by the country of the Helvetii, on the east by Noricum, on the north by Vindelicia, on the west by Cisalpine Gaul and on south by Venetia et Histria...

 (annexed 15 BC), Noricum

Noricum

Noricum, in ancient geography, was a Celtic kingdom stretching over the area of today's Austria and a part of Slovenia. It became a province of the Roman Empire...

 (16 BC), Pannonia

Pannonia

Pannonia was an ancient province of the Roman Empire bounded north and east by the Danube, coterminous westward with Noricum and upper Italy, and southward with Dalmatia and upper Moesia....

 (9 BC) and Moesia

Moesia

Moesia was an ancient region and later Roman province situated in the Balkans, along the south bank of the Danube River. It included territories of modern-day Southern Serbia , Northern Republic of Macedonia, Northern Bulgaria, Romanian Dobrudja, Southern Moldova, and Budjak .-History:In ancient...

 (6 AD), becoming, with Illyricum, the Principate's most important source of auxiliary recruits for its entire duration. In the East, where the Syrians already provided the bulk of the Roman army's archers, Augustus annexed Galatia

Galatia

Ancient Galatia was an area in the highlands of central Anatolia in modern Turkey. Galatia was named for the immigrant Gauls from Thrace , who settled here and became its ruling caste in the 3rd century BC, following the Gallic invasion of the Balkans in 279 BC. It has been called the "Gallia" of...

 (25 BC) and Judaea: the former, a region in central Anatolia with a Celtic-speaking people, became an important source of recruits. In N. Africa, Egypt, Cyrene

Cyrene, Libya

Cyrene was an ancient Greek colony and then a Roman city in present-day Shahhat, Libya, the oldest and most important of the five Greek cities in the region. It gave eastern Libya the classical name Cyrenaica that it has retained to modern times.Cyrene lies in a lush valley in the Jebel Akhdar...

, and Numidia

Numidia

Numidia was an ancient Berber kingdom in part of present-day Eastern Algeria and Western Tunisia in North Africa. It is known today as the Chawi-land, the land of the Chawi people , the direct descendants of the historical Numidians or the Massyles The kingdom began as a sovereign state and later...

 (25 BC) were added to the empire. Numidia (modern day Eastern Algeria) was home to the Mauri

Mauretania

Mauretania is a part of the historical Ancient Libyan land in North Africa. It corresponds to present day Morocco and a part of western Algeria...

, the ancestors of today's Berber people

Berber people

Berbers are the indigenous peoples of North Africa west of the Nile Valley. They are continuously distributed from the Atlantic to the Siwa oasis, in Egypt, and from the Mediterranean to the Niger River. Historically they spoke the Berber language or varieties of it, which together form a branch...

. Their light cavalry (equites Maurorum) was highly prized and had alternately fought and assisted the Romans for well over two centuries: they now started to be recruited into the regular auxilia. Even more Mauri units were formed after the annexation of Mauretania

Mauretania

Mauretania is a part of the historical Ancient Libyan land in North Africa. It corresponds to present day Morocco and a part of western Algeria...

 (NW Algeria, Morocco), the rest of the Berber homeland, in 44 AD by emperor Claudius

Claudius

Claudius , was Roman Emperor from 41 to 54. A member of the Julio-Claudian dynasty, he was the son of Drusus and Antonia Minor. He was born at Lugdunum in Gaul and was the first Roman Emperor to be born outside Italy...

 (ruled 41–54).

Recruitment was thus heavy throughout the Augustan period, with a steady increase in the number of units formed. By 23 AD, the Roman historian Tacitus

Tacitus

Publius Cornelius Tacitus was a senator and a historian of the Roman Empire. The surviving portions of his two major works—the Annals and the Histories—examine the reigns of the Roman Emperors Tiberius, Claudius, Nero and those who reigned in the Year of the Four Emperors...

 records that there were roughly the same numbers of auxiliaries in service as there were legionaries. Since at this time there were 25 legions of ca. 5,000 men each, the auxilia thus amounted to ca. 125,000 men, implying ca. 250 auxiliary regiments.

Illyrian revolt (6–9 AD)

During the early Julio-Claudian period, many auxiliary regiments raised in frontier provinces were stationed in or near their home provinces, except during periods of major crises such as the Cantabrian Wars

Cantabrian Wars

The Cantabrian Wars occurred during the Roman conquest of the modern provinces of Cantabria, Asturias and León, against the Asturs and the Cantabri. They were the final stage of the conquest of Hispania.-Antecedents:...

, when they were deployed temporarily in theatre. This carried the obvious risk if their own tribe or ethnic group rebelled against Rome (or attacked the Roman frontier from outside the Empire), auxiliary troops could be tempted to make common cause with them. The Romans would then be faced by an enemy that included units fully equipped and trained by themselves, thus losing their usual tactical advantages over tribal foes.

Arminius

Arminius

Arminius , also known as Armin or Hermann was a chieftain of the Germanic Cherusci who defeated a Roman army in the Battle of the Teutoburg Forest...

 is the classic example at an individual level: after several years of serving in Rome's forces as prefect of an auxiliary unit, he used the military training and experience he had gained to lead a confederacy of German tribes against Rome, culminating in the destruction of three Roman legions in the Teutoberg Forest

Battle of the Teutoburg Forest

The Battle of the Teutoburg Forest took place in 9 CE, when an alliance of Germanic tribes led by Arminius of the Cherusci ambushed and decisively destroyed three Roman legions, along with their auxiliaries, led by Publius Quinctilius Varus.Despite numerous successful campaigns and raids by the...

 in 9 AD, and the abandonment of Augustus' strategy of annexing Germany as far as the Elbe

Elbe

The Elbe is one of the major rivers of Central Europe. It rises in the Krkonoše Mountains of the northwestern Czech Republic before traversing much of Bohemia , then Germany and flowing into the North Sea at Cuxhaven, 110 km northwest of Hamburg...

 river. (This strategy was never revived by later emperors).

At a collective level, the risk was even greater, as the hugely dangerous Illyrian revolt

Great Illyrian revolt

The Great Illyrian Revolt, was a major conflict between an alliance of indigenous communities from Illyricum and Roman forces that lasted for four years beginning in AD 6 and ending in AD 9.-The war:...

 proved. The central Illyrian tribes were tough and spartan shepherds of the Bosnian

Bosnia (region)

Bosnia is a eponomous region of Bosnia and Herzegovina. It lies mainly in the Dinaric Alps, ranging to the southern borders of the Pannonian plain, with the rivers Sava and Drina marking its northern and eastern borders. The other eponomous region, the southern, other half of the country is...

 mountains and excellent soldier-material. Their territory formed part of the strategic province of Illyricum, recently expanded to include the territory of the Pannonii, an Illyrian tribe based on the west bank of the Danube

Danube

The Danube is a river in the Central Europe and the Europe's second longest river after the Volga. It is classified as an international waterway....

 who were subjugated by Rome in 12–9 BC. By the start of the Common Era, they were an important recruitment base for the auxilia. But discontent was festering among the Illyrian tribes due to what they saw as the rapacity of Roman tax officials. In 6 AD, several regiments of Dalmatae

Dalmatae

The Dalmatae or Delmatae were an ancient people who inhabited the core of what would then become known as Dalmatia after the Roman conquest - now the eastern Adriatic coast in Croatia, between the rivers Krka and Neretva...

, a warlike Illyrian tribe, were ordered to gather in one place to prepare to join Augustus' stepson and senior military commander Tiberius

Tiberius

Tiberius , was Roman Emperor from 14 AD to 37 AD. Tiberius was by birth a Claudian, son of Tiberius Claudius Nero and Livia Drusilla. His mother divorced Nero and married Augustus in 39 BC, making him a step-son of Octavian...

 in a war against the Germans. Instead they mutinied at the assembly point, and defeated a Roman force sent against them. The Dalmatae were soon joined by the Breuci, another Illyrian tribe that supplied several auxiliary regiments. They gave battle to a second Roman force from Moesia

Moesia

Moesia was an ancient region and later Roman province situated in the Balkans, along the south bank of the Danube River. It included territories of modern-day Southern Serbia , Northern Republic of Macedonia, Northern Bulgaria, Romanian Dobrudja, Southern Moldova, and Budjak .-History:In ancient...

. They lost, but inflicted heavy casualties. The rebels were now joined by a large number of other Illyrian tribes. The Dalmatae attacked Salona

Salona

Salona was an ancient Illyrian Delmati city in the first millennium BC. The Greeks had set up an emporion there. After the conquest by the Romans, Salona became the capital of the Roman province of Dalmatia...

 and overran the Adriatic coast, defeating a Roman force and exposing the Roman heartland of Italy to the fear of a rebel invasion.

Augustus ordered Tiberius to break off operations in Germany and move his main army to Illyricum. When it became clear that even Tiberius' forces were insufficient, Augustus was obliged to raise a second task force under Tiberius' nephew Germanicus

Germanicus

Germanicus Julius Caesar , commonly known as Germanicus, was a member of the Julio-Claudian dynasty and a prominent general of the early Roman Empire. He was born in Rome, Italia, and was named either Nero Claudius Drusus after his father or Tiberius Claudius Nero after his uncle...

, resorting to the compulsory purchase and emancipation of thousands of slaves to find enough troops, for the first time since the aftermath of the Battle of Cannae two centuries earlier. The Romans had now deployed no less than 15 legions and an equivalent number of auxilia. This amounts to a total of ca. 150,000 men, including at least 50 auxiliary cohorts composed, exceptionally, of Roman citizens. These were men whose status or background was regarded by Augustus as unsuitable for recruitment into the legions: either natural-born citizens of the lowest category including vagrants and convicted criminals, or the freed slaves (Roman law accorded citizenship to the freed slaves of Roman citizens). These special units were accorded the title civium Romanorum ("of Roman citizens"), or c.R. for short. After the Illyrian revolt, these cohorts remained in being and recruited non-citizens like other auxiliary units, but retained their prestigious c.R. title. In addition, the regular forces were assisted by a large number of allied troops from neighbouring Thrace

Odrysian kingdom

The Odrysian kingdom was a union of Thracian tribes that endured between the 5th and 3rd centuries BC. It consisted largely of present-day Bulgaria, spreading to parts of Northern Dobruja, parts of Northern Greece and modern-day European Turkey...

 deployed by their king Rhoemetalces I

Rhoemetalces I

Rhoemetalces I was king of the Odrysian kingdom of Thrace from 12 BC to 12, in succession to his nephew Rhescuporis I.Rhoemetalces I was a loyal ally to the first Roman Emperor Augustus. He was a direct descendant of the Thracian King Cotys I, and the middle son of the earlier Thracian king Cotys VI...

, a Roman amicus (puppet king).

The Romans faced further reverses on the battlefield and a savage guerrilla war in the Bosnian mountains. It took them three years of hard fighting to quell the revolt, which was described by the Roman historian Suetonius

Suetonius

Gaius Suetonius Tranquillus, commonly known as Suetonius , was a Roman historian belonging to the equestrian order in the early Imperial era....

 as the most difficult conflict faced by Rome since the Punic Wars

Punic Wars

The Punic Wars were a series of three wars fought between Rome and Carthage from 264 B.C.E. to 146 B.C.E. At the time, they were probably the largest wars that had ever taken place...

 two centuries earlier. Tiberius finally succeeded in quelling the revolt in 9 AD. This was just in time: that same year Arminius destroyed Varus

Publius Quinctilius Varus

Publius Quinctilius Varus was a Roman politician and general under Emperor Augustus, mainly remembered for having lost three Roman legions and his own life when attacked by Germanic leader Arminius in the Battle of the Teutoburg Forest.-Life:His paternal grandfather was senator Sextus Quinctilius...

' three legions in Germany. The Roman high command had no doubt that Arminius would have formed a grand alliance with the Illyrians.

Despite the gravity of this rebellion, the Illyrians went on to become the backbone of the Roman army. By the 2nd century, with roughly half the Roman army deployed on the Danube frontier, the auxilia and legions alike were dominated by Illyrian recruits. In the 3rd century, Illyrians largely replaced Italians in the senior officer echelons of praefecti of auxiliary regiments and tribuni militum of legions. Finally, from 268 to 379 AD, virtually all emperors, including Diocletian

Diocletian

Diocletian |latinized]] upon his accession to Diocletian . c. 22 December 244  – 3 December 311), was a Roman Emperor from 284 to 305....

 and Constantine the Great

Constantine I

Constantine the Great , also known as Constantine I or Saint Constantine, was Roman Emperor from 306 to 337. Well known for being the first Roman emperor to convert to Christianity, Constantine and co-Emperor Licinius issued the Edict of Milan in 313, which proclaimed religious tolerance of all...

 were Romanised Illyrians from the provinces of Dalmatia

Dalmatia

Dalmatia is a historical region on the eastern coast of the Adriatic Sea. It stretches from the island of Rab in the northwest to the Bay of Kotor in the southeast. The hinterland, the Dalmatian Zagora, ranges from fifty kilometers in width in the north to just a few kilometers in the south....

, Moesia Superior and Pannonia

Pannonia

Pannonia was an ancient province of the Roman Empire bounded north and east by the Danube, coterminous westward with Noricum and upper Italy, and southward with Dalmatia and upper Moesia....

. These were members of a military aristocracy, outstanding soldiers who saved the empire from collapse in the turbulent late 3rd century.

Later Julio-Claudians (14–68 AD)

Significant development of the auxilia appears to have taken place during the rule of the emperor Claudius

Claudius

Claudius , was Roman Emperor from 41 to 54. A member of the Julio-Claudian dynasty, he was the son of Drusus and Antonia Minor. He was born at Lugdunum in Gaul and was the first Roman Emperor to be born outside Italy...

 (41–54 AD).

A minimum term of service of 25 years was established, at the end of which the retiring auxiliary soldier, and all his children, were awarded Roman citizenship. This is deduced from the fact that the first known Roman military diplomas date from the time of Claudius. This was a folding bronze tablet engraved with the details of the soldier's service record, which he could use to prove his citizenship. Claudius also decreed that prefects of auxiliary regiments must all be of equestrian rank, thus excluding centurions from such commands. The fact that auxiliary commanders were now all of the same social rank as most tribuni militum

Tribune

Tribune was a title shared by elected officials in the Roman Republic. Tribunes had the power to convene the Plebeian Council and to act as its president, which also gave them the right to propose legislation before it. They were sacrosanct, in the sense that any assault on their person was...

, (military tribunes, a legion's senior staff officers, all of whom only one, the tribunus laticlavius, was of the higher senatorial rank), probably indicates that auxilia now enjoyed greater prestige. Indigenous chiefs continued to command some auxiliary regiments, and were probably granted equestrian rank for the purpose. It is also likely that auxiliary pay was standardised at this time, but we only have estimates for the Julio-Claudian period.

Auxiliary uniform, armour, weapons and equipment were probably standardised by the end of the Julio-Claudian period. Auxiliary equipment was broadly similar to that of the legions (see Section 2.1 below for possible differences in armour). By 68 AD, there was little difference between most auxiliary infantry and their legionary counterparts in equipment, training and fighting capability. The main difference was that auxilia contained combat cavalry, both heavy and light, and other specialized units that legions lacked.

Claudius annexed to the empire three regions that became important sources of auxiliary recruits: Britannia

Britannia

Britannia is an ancient term for Great Britain, and also a female personification of the island. The name is Latin, and derives from the Greek form Prettanike or Brettaniai, which originally designated a collection of islands with individual names, including Albion or Great Britain. However, by the...

 (43 AD), and the former client kingdoms of Mauretania

Mauretania

Mauretania is a part of the historical Ancient Libyan land in North Africa. It corresponds to present day Morocco and a part of western Algeria...

 (44) and Thracia

Thrace

Thrace is a historical and geographic area in southeast Europe. As a geographical concept, Thrace designates a region bounded by the Balkan Mountains on the north, Rhodope Mountains and the Aegean Sea on the south, and by the Black Sea and the Sea of Marmara on the east...

 (46). The latter became as important as Illyria as a source of auxiliary recruits, especially cavalry and archers. Britain in mid-2nd century contained the largest number of auxiliary regiments in any single province: about 60 out of about 400 (15%). By the rule of Nero

Nero

Nero , was Roman Emperor from 54 to 68, and the last in the Julio-Claudian dynasty. Nero was adopted by his great-uncle Claudius to become his heir and successor, and succeeded to the throne in 54 following Claudius' death....

 (54–68), auxiliary numbers may have reached, by one estimate, about 200,000 men, implying about 400 regiments.

Revolt of the Batavi (69–70 AD)

The Batavi

Batavi

Batavi - Latin for Batavians - is an open source webshop under the GNU General Public License. The development of Batavi started in 2007 inspired by a preliminary osCommerce 3.0 version, a version that seemed to be never finished by the osCommerce team...

, a Germanic tribe, inhabited the region today known as Gelderland

Gelderland

Gelderland is the largest province of the Netherlands, located in the central eastern part of the country. The capital city is Arnhem. The two other major cities, Nijmegen and Apeldoorn have more inhabitants. Other major regional centers in Gelderland are Ede, Doetinchem, Zutphen, Tiel, Wijchen,...

 (Netherlands

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

), in the Rhine river delta

River delta

A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...

, then known as the Insula Batavorum ("Island of the Batavi", because surrounded by branches of the Rhine), part of the Roman province of Germania Inferior

Germania Inferior

Germania Inferior was a Roman province located on the left bank of the Rhine, in today's Luxembourg, southern Netherlands, parts of Belgium, and North Rhine-Westphalia left of the Rhine....

. They were a warlike people, skilled horsemen, boatmen and swimmers. In return for the unusual privilege of exemption from tributum (direct taxes on land and heads normally exacted from peregrini), they supplied a disproportionate number of recruits to the Julio-Claudian auxilia: one ala and eight cohortes. They also provided most of Augustus' elite personal bodyguard unit (the Germani corpore custodes), which continued in service until 68 AD. The Batavi auxilia amounted to about 5,000 men, implying that during the entire Julio-Claudian period, over 50% of all Batavi males reaching military age (16 years) may have enlisted in the auxilia. Thus the Batavi, although just 0.05% of the total population of the empire of ca. 70 million in 23 AD, supplied about 4% of the total auxilia i.e. 80 times their proportionate share. They were regarded by the Romans as the very best (fortissimi, validissimi) of their auxiliary, and indeed all, their forces. In Roman service, both their cavalry and infantry had perfected a technique for swimming across rivers wearing full armour and weapons.

Julius Civilis

Gaius Julius Civilis

Gaius Julius Civilis was the leader of the Batavian rebellion against the Romans in 69. By his nomen, it can be told that he was made a Roman citizen by either Augustus or Caligula....

 (literally: "Julius the Citizen", clearly a Latin name adopted on gaining Roman citizenship

Roman citizenship

Citizenship in ancient Rome was a privileged political and legal status afforded to certain free-born individuals with respect to laws, property, and governance....

, not his native one) was a hereditary prince of the Batavi and the prefect of a Batavi cohort. A veteran of 25 years' service, he had distinguished himself by service in Britain, where he and the eight Batavi cohorts had played a crucial role in both the Roman invasion

Roman conquest of Britain

The Roman conquest of Britain was a gradual process, beginning effectively in AD 43 under Emperor Claudius, whose general Aulus Plautius served as first governor of Britannia. Great Britain had already frequently been the target of invasions, planned and actual, by forces of the Roman Republic and...

 in 43 AD and the subsequent subjugation of southern Britain.

By 69, however, Civilis, the Batavi regiments and the Batavi people had become utterly disaffected with Rome. After the Batavi regiments were withdrawn from Britain to Italy in 66, Civilis and his brother (also a prefect) were arrested by the governor of Germania Inferior

Roman governors of Germania Inferior

This is a list of Roman governors of Germania Inferior . Capital and largest city of Germania Inferior was Colonia Claudia Ara Agrippinensium , modern-day Cologne....

 on a fabricated accusation of sedition. The governor ordered his brother's execution, while Civilis, who as a Roman citizen had the right to appeal to the emperor, was sent to Rome in chains for judgement by Nero. He was released by Nero's overthrower and successor, Galba

Galba

Galba , was Roman Emperor for seven months from 68 to 69. Galba was the governor of Hispania Tarraconensis, and made a bid for the throne during the rebellion of Julius Vindex...

, but the latter also disbanded the imperial bodyguard unit for their loyalty to Nero. This alienated several hundred crack Batavi troops, and indeed the whole Batavi nation who regarded it as a grave insult. At the same time, relations collapsed between the Batavi cohorts and the legion to which they had been attached since the invasion of Britain 25 years earlier (XIV Gemina

Legio XIV Gemina

Legio quarta decima Gemina was a legion of the Roman Empire, levied by Julius Caesar in late 58 B.C. The cognomen Gemina suggests that the legion resulted from fusion of two previous ones, one of them being the Fourteenth legion that fought in the Battle of Alesia, the other being the Martia ...

). Their mutual hatred erupted in open fighting on at least two occasions.

At this juncture, the Roman empire was convulsed by its first major civil war since the Battle of Actium

Battle of Actium

The Battle of Actium was the decisive confrontation of the Final War of the Roman Republic. It was fought between the forces of Octavian and the combined forces of Mark Antony and Cleopatra VII. The battle took place on 2 September 31 BC, on the Ionian Sea near the city of Actium, at the Roman...

 exactly a century earlier: the Year of the Four Emperors

Year of the Four Emperors

The Year of the Four Emperors was a year in the history of the Roman Empire, AD 69, in which four emperors ruled in a remarkable succession. These four emperors were Galba, Otho, Vitellius, and Vespasian....

 (69-70 AD). The governor of Germania Inferior, ordered to raise more troops, outraged the Batavi by attempting to conscript more Batavi than the maximum stipulated in their treaty. The brutality and corruption of the Roman recruiting-centurions (including incidents of sexual assault on Batavi young men) brought already deep discontent in the Batavi homeland to the boil.

Civilis now led his people in open revolt. Initially, he claimed he was supporting the bid for power of Vespasian

Vespasian

Vespasian , was Roman Emperor from 69 AD to 79 AD. Vespasian was the founder of the Flavian dynasty, which ruled the Empire for a quarter century. Vespasian was descended from a family of equestrians, who rose into the senatorial rank under the Emperors of the Julio-Claudian dynasty...

, the general in command of the legions in Syria

Syria (Roman province)

Syria was a Roman province, annexed in 64 BC by Pompey, as a consequence of his military presence after pursuing victory in the Third Mithridatic War. It remained under Roman, and subsequently Byzantine, rule for seven centuries, until 637 when it fell to the Islamic conquests.- Principate :The...

, whom Civilis had probably befriended when both were involved in the Roman invasion 25 years before (Vespasian was then commander of the legion II Augusta

Legio II Augusta

Legio secunda Augusta , was a Roman legion, levied by Gaius Vibius Pansa Caetronianus in 43 BC, and still operative in Britannia in the 4th century...

). But the uprising soon became a bid for independence. Civilis exploited the fact that some legions were absent from the Rhine area due to the civil war, and the rest under-strength. In addition, the Roman commanders and their rank-and-file soldiers were divided by loyalty to rival emperors. Civilis quickly won the support of the Batavi's neighbours and kinsmen, the Cananefates, who in turn won over the Frisii

Frisii

The Frisii were an ancient Germanic tribe living in the low-lying region between the Zuiderzee and the River Ems. In the Germanic pre-Migration Period the Frisii and the related Chauci, Saxons, and Angles inhabited the Continental European coast from the Zuyder Zee to south Jutland...

. First the rebel allies captured two Roman forts in their territory, and a cohort of Tungri

Tungri

The Tungri were a tribe, or group of tribes, who lived in the Belgic part Gaul, during the times of the Roman empire. They were described by Tacitus as being the same people who were first called "Germani" , meaning that all other tribes who were later referred to this way, including those in...

 defected to Civilis. Then two legions sent against Civilis were defeated when their companion Batavi ala defected to his side. The Classis Germanica (Rhine flotilla), largely manned by Batavi, was seized by Civilis. Most importantly, the eight Batavi cohorts stationed at Mainz with XIV Gemina mutinied and joined him, defeating at Bonn

Bonn

Bonn is the 19th largest city in Germany. Located in the Cologne/Bonn Region, about 25 kilometres south of Cologne on the river Rhine in the State of North Rhine-Westphalia, it was the capital of West Germany from 1949 to 1990 and the official seat of government of united Germany from 1990 to 1999....

 a Roman force that attempted to block their return to their homeland. By now, Civilis commanded at least 12 regiments (6,000 men) of Roman-trained and equipped auxiliary troops, as well as a much larger number of tribal levies. A number of German tribes from beyond the Rhine joined his cause. Several other German and Gallic units sent against him deserted, as the revolt spread to the rest of Gallia Belgica

Gallia Belgica

Gallia Belgica was a Roman province located in what is now the southern part of the Netherlands, Belgium, Luxembourg, northeastern France, and western Germany. The indigenous population of Gallia Belgica, the Belgae, consisted of a mixture of Celtic and Germanic tribes...

, including the Tungri, Lingones

Lingones

Lingones were a Celtic tribe that originally lived in Gaul in the area of the headwaters of the Seine and Marne rivers. Some of the Lingones migrated across the Alps and settled near the mouth of the Po River in Cisalpine Gaul of northern Italy around 400 BCE. These Lingones were part of a wave of...

 and Treviri

Treveri

The Treveri or Treviri were a tribe of Gauls who inhabited the lower valley of the Moselle from around 150 BCE, at the latest, until their eventual absorption into the Franks...

 tribes. He was able to destroy the two remaining legions in Germania Inferior, (V Alaudae

Legio V Alaudae

Legio quinta Alaudae sometimes known as Gallica, was levied by Julius Caesar in 52 BC from native Gauls. Their emblem was an elephant, and their cognomen Alaudae came from the high crest on their helmets, typical of the Gauls, which made them look like larks...

and XV Primigenia

Legio XV Primigenia

Legio quinta decima Primigenia - a name of the goddess Fortuna) was a legion of the Roman army.It was originally levied by the emperor Caligula in 39, to aid in the Germanic campaigns and was stationed in the Rhine frontier until 70, when it was destroyed during the Batavian rebellion with the V...

).

By this stage Rome's entire position on the Rhine and even in Gaul was imperiled. Their civil war over, the Romans mustered a huge task force of eight legions (five dispatched from Italy, two from Spain and one from Britain) to deal with Civilis. Its commander Petillius Cerialis

Quintus Petillius Cerialis

Quintus Petilius Cerialis Caesius Rufus was a Roman general and administrator who served in Britain during Boudica's rebellion and who went on to participate in the civil wars after the death of Nero. He later defeated the rebellion of Julius Civilis and returned to Britain as its governor.His...

 had to fight two difficult battles, at Trier

Trier

Trier, historically called in English Treves is a city in Germany on the banks of the Moselle. It is the oldest city in Germany, founded in or before 16 BC....

 and Xanten

Xanten

Xanten is a historic town in the North Rhine-Westphalia state of Germany, located in the district of Wesel.Xanten is known for the Archaeological Park or archaeological open air museum , its medieval picturesque city centre with Xanten Cathedral and many museums, its large man-made lake for...

, before he could overrun the Batavi's homeland. Tacitus' surviving narrative breaks off as he describes a meeting on an island in the Rhine delta between Civilis and Cerialis to discuss peace terms. We do not know the outcome of this meeting or Civilis' ultimate fate. But in view of his former friendship with Vespasian, who had already offered him a pardon, and the fact that the Romans still needed the Batavi levies, it is likely that the terms were lenient by Roman standards.

Petilius Cerialis took a number of reconstituted Batavi units with him to Britain, and the Batavi regiments continued to serve with special distinction in Britain and elsewhere for the rest of the 1st century and beyond. Even as late as 395, units with the Batavi name, although long since composed of recruits from all over the empire, were still classified as elite palatini

Palatini (Roman military)

The palatini were elite regiments of the Late Roman army mostly attached to the comitatus praesentales, or imperial escort armies...

, e.g. the equites Batavi seniores (cavalry) and auxilium Batavi seniores (infantry).

Flavian era (69–96 AD)

The revolt of the Batavi appears to have led to a significant change in the Roman government's policy on auxiliary deployment. The revolt proved that in times of civil strife, when legions were far from their bases campaigning for rival claimants to the imperial throne, it was dangerous to leave provinces exclusively in the hands of auxiliary regiments recruited from the indigenous nation. During the Julio-Claudian period, auxiliary regiments had often been deployed away from their original home province. But in the Flavian period (69–96), this appears to have become standard policy. Thus in 70 AD five reconstituted Batavi regiments (one ala and four cohortes) were transferred to Britain under Petillius Cerialis, who had suppressed the Civilis revolt and then embarked on the governorship of the island. The great majority of regiments probably founded in the 1st century were stationed away from their province of origin in the second e.g. of 13 British regiments recorded in mid 2nd century, none were stationed in Britain. Furthermore, it appears that in the Flavian era native nobles were no longer permitted to command auxiliary units from their own nation.

After a prolonged period in a foreign province a regiment would become assimilated, since the majority of its new recruits would be drawn from the province in which it was stationed, or neighbouring provinces. Those same "British" units, mostly based on the Danube frontier, would by ca. 150, after almost a century away from their home island, be largely composed of Illyrian, Thracian and Dacian recruits. However, there is evidence that a few regiments at least continued to draw some recruits from their original home provinces in the 2nd century e.g. Batavi units stationed in Britain.

The Flavian period also saw the first formation of large, double-size units, both infantry and cavalry, of a nominal strength of 1,000 men (cohors/ala milliaria), though they were actually mostly smaller (720 for an ala milliaria and 800 for a cohors milliaria). These were the mirror image of the double-strength first cohorts of legions also introduced at this time. Such units remained a minority of the auxilia: in mid-2nd century, they constituted 13% of units, containing 20% of total manpower.

Later Principate (97–284)

In 106 AD, emperor Trajan finally defeated the Dacian

Dacians

The Dacians were an Indo-European people, very close or part of the Thracians. Dacians were the ancient inhabitants of Dacia...

 kingdom of Decebalus

Decebalus

Decebalus or "The Brave" was a king of Dacia and is famous for fighting three wars and negotiating two interregnums of peace without being eliminated against the Roman Empire under two emperors...

 and annexed it as the Roman province of Dacia Traiana

Roman Dacia

The Roman province of Dacia on the Balkans included the modern Romanian regions of Transylvania, Banat and Oltenia, and temporarily Muntenia and southern Moldova, but not the nearby regions of Moesia...

. By mid 2nd century, there were 44 auxiliary regiments stationed there, about 10% of the total auxilia. In Britain there were 60. Together these two provinces contained about a quarter of the total auxiliary regiments.

There is some discrepancy about the precise size of the auxilia during the rule of Trajan's successor, Hadrian

Hadrian

Hadrian , was Roman Emperor from 117 to 138. He is best known for building Hadrian's Wall, which marked the northern limit of Roman Britain. In Rome, he re-built the Pantheon and constructed the Temple of Venus and Roma. In addition to being emperor, Hadrian was a humanist and was philhellene in...

 (117-138) between the two most up-to-date global analyses of the Roman auxilia, by Spaul (2000) and Holder (2003)

ESTIMATES OF ROMAN AUXILIA NUMBERS (mid 2nd century)
! Author !! No. Alae !! No. Cohortes !! Total no. units !! Total cavalry !! Total infantry !! Total effectives

J. Spaul (2000)	80	247	327	56,160	124,640	180,800
P. A. Holder (2003)	88	279	367	74,624	143,200	217,624

NOTE: Manpower figures exclude officers (centurions and decurions), which would have numbered about 3,500 men overall.

In addition, Holder believes that a further 14 cohortes, which are attested under Trajan, immediately before Hadrian's rule, but not during or after it, were probably in existence at this time, giving a total of 381 units and 225,000 effectives. The discrepancy between the two scholars is due to: (i) Interpretation of units with the same name and number, but attested in different provinces in the same period. Spaul tends to take a more cautious approach and to assume such are the same unit moving base frequently, while Holder tends to regard them as separate units which acquired the same number due to double (or triple) seriation. (ii) Assumptions about how many cohortes were equitatae. Spaul accepts only those cohortes specifically attested as equitatae i.e., about 40% of recorded units. Holder estimates that at least 70% of cohortes contained cavalry contingents by the early 2nd century

Even according to the more conservative estimate, the auxilia were by this time significantly larger than the legions, which contained ca. 155,000 effectives (28 legions of 5,500 men each) at this time, of which just 3,360 were cavalry. (For a detailed breakdown, see section 4: Auxilia deployment in the 2nd century, below).

During the second half of the 2nd century, the Roman army underwent considerable further expansion, with the addition of 5 new legions (27,500 men) to a peak of 33. An equivalent number of auxilia (i.e. 50–60 new regiments) were probably added, perhaps reaching a peak of ca. 440 regiments and over 250,000 effectives by the end of Septimius Severus

Septimius Severus

Septimius Severus , also known as Severus, was Roman Emperor from 193 to 211. Severus was born in Leptis Magna in the province of Africa. As a young man he advanced through the customary succession of offices under the reigns of Marcus Aurelius and Commodus. Severus seized power after the death of...

's rule (211 AD).

The likely growth of the Roman auxilia may be summarised as follows:

ROMAN ARMY NUMBERS 24–305 AD
! Army corps !! Tiberius
24 AD !! Hadrian
ca. 130 AD !! S. Severus
211 AD !! 3rd c. crisis
ca. 270 AD !! Diocletian
284–305

LEGIONS	125,000	155,000	182,000
AUXILIA	125,000	218,000	250,000
PRAETORIAN GUARD	~~5,000	~10,000	~10,000
Total Roman Army	255,000	383,000	442,000	290,000?	390,000

NOTE: Figures are based on official (not actual) unit strengths and exclude Roman Navy

Roman Navy

The Roman Navy comprised the naval forces of the Ancient Roman state. Although the navy was instrumental in the Roman conquest of the Mediterranean basin, it never enjoyed the prestige of the Roman legions...

 effectives and barbarian foederati.

During the 2nd century some units with the new names numerus ("group") and vexillatio ("detachment") appear in the diploma record. Their size is uncertain, but was likely smaller than the regular alae and cohortes, as originally they were probably detachments from the latter, acquiring independent status after long-term separation. As these units are mentioned in diplomas, they were presumably part of the regular auxiliary organisation. But numeri was also a generic term used for barbarian units outside the regular auxilia. (see section 2.4 Irregular units, below).

In 212, the constitutio Antoniniana

Constitutio Antoniniana

The Constitutio Antoniniana was an edict issued in 212 AD, by the Roman Emperor Caracalla...

(Antonine decree) of emperor Caracalla

Caracalla

Caracalla , was Roman emperor from 198 to 217. The eldest son of Septimius Severus, he ruled jointly with his younger brother Geta until he murdered the latter in 211...

 granted Roman citizenship to all the free inhabitants of the Empire – the peregrini – thus abolishing their second-class status. But there is no evidence that the citizens-only rule for legions was also abolished at this time. The legions simply gained a much wider recruitment base, as they were now able to recruit any male free resident of the empire. Auxiliary units were now recruited mainly from Roman citizens, but probably continued to recruit non-citizen barbari from outside the Empire's borders. However, the citizens-only rule for legions appears to have been dropped some time during the 3rd century, as by the 4th century Romans and barbarians are found serving together in all units.

In the mid to late 3rd century, the army was afflicted by a combination of military disasters and of pestilence, the so-called Crisis of the Third Century

Crisis of the Third Century

The Crisis of the Third Century was a period in which the Roman Empire nearly collapsed under the combined pressures of invasion, civil war, plague, and economic depression...

. In 251–271 Gaul, the Alpine regions and Italy, the Balkans and the East were simultaneously overrun by Alamanni, Sarmatians, Goths and Persians respectively. At the same time, the Roman army was struggling with the effects of a devastating pandemic, probably of smallpox

Smallpox

Smallpox was an infectious disease unique to humans, caused by either of two virus variants, Variola major and Variola minor. The disease is also known by the Latin names Variola or Variola vera, which is a derivative of the Latin varius, meaning "spotted", or varus, meaning "pimple"...

: the Plague of Cyprian

Plague of Cyprian

The Plague of Cyprian is the name given to a pandemic, probably of smallpox, that afflicted the Roman Empire from AD 250 onwards. It was still raging in 270, when it claimed the life of emperor Claudius II Gothicus . The plague caused widespread manpower shortages in agriculture and the Roman army....

 which began in 251 and was still raging in 270, when it claimed the life of emperor Claudius II Gothicus. The evidence for an earlier pandemic, the Antonine Plague

Antonine Plague

The Antonine Plague, AD 165–180, also known as the Plague of Galen, who described it, was an ancient pandemic, either of smallpox or measles, brought back to the Roman Empire by troops returning from campaigns in the Near East...

 (also smallpox) indicates a mortality of 15–30% in the empire as a whole. The armies would likely have suffered deaths at the top end of the range, due to their close concentration of individuals and frequent movements across the empire. This probably led to a steep decline in military numbers, which only recovered at the end of the century under Diocletian

Diocletian

Diocletian |latinized]] upon his accession to Diocletian . c. 22 December 244  – 3 December 311), was a Roman Emperor from 284 to 305....

 (r. 284–305).

The recruitment shortfall caused by the crisis seems to have led to recruitment of barbarians to the auxilia on a much greater scale than previously. By the 4th century, it has been estimated that some 25% of regular army recruits were barbarian-born. In the elite palatini regiments anywhere between a third and a half of recruits may have been barbarian. This is likely a much greater proportion of foreigners than joined the auxilia in the 1st-2nd centuries. In the 3rd century, a small number of regular auxiliary units appear in the record that, for the first time, bear the names of barbarian tribes from outside the empire e.g. the ala I Sarmatarum attested in 3rd-century Britain. This was probably an offshoot of the 5,500 surrendered Sarmatian horsemen posted on Hadrian's Wall

Hadrian's Wall

Hadrian's Wall was a defensive fortification in Roman Britain. Begun in AD 122, during the rule of emperor Hadrian, it was the first of two fortifications built across Great Britain, the second being the Antonine Wall, lesser known of the two because its physical remains are less evident today.The...

 by emperor Marcus Aurelius in ca. 175. This unit may be an early example of a novel process whereby irregular units of barbari (foederati) were transformed into regular auxilia. This process intensified in the 4th century: the Notitia Dignitatum

Notitia Dignitatum

The Notitia Dignitatum is a unique document of the Roman imperial chanceries. One of the very few surviving documents of Roman government, it details the administrative organisation of the eastern and western empires, listing several thousand offices from the imperial court down to the provincial...

, a key document on the late Roman army

Late Roman army

The Late Roman army is the term used to denote the military forces of the Roman Empire from the accession of Emperor Diocletian in 284 until the Empire's definitive division into Eastern and Western halves in 395. A few decades afterwards, the Western army disintegrated as the Western empire...

, lists a large number of regular units with barbarian names.

4th century

In the 4th century, the Roman army underwent a radical restructuring. In the rule of Diocletian

Diocletian

Diocletian |latinized]] upon his accession to Diocletian . c. 22 December 244  – 3 December 311), was a Roman Emperor from 284 to 305....

 (284–305), the traditional Principate formations of legiones, alae and cohortes appear to have been broken up into smaller units, many of which bore a variety of new names. Under Constantine I

Constantine I

Constantine the Great , also known as Constantine I or Saint Constantine, was Roman Emperor from 306 to 337. Well known for being the first Roman emperor to convert to Christianity, Constantine and co-Emperor Licinius issued the Edict of Milan in 313, which proclaimed religious tolerance of all...

 (r. 312–337) it appears that military units were classified into three grades based on strategic role and to some extent quality: palatini

Palatini (Roman military)

The palatini were elite regiments of the Late Roman army mostly attached to the comitatus praesentales, or imperial escort armies...

, elite units normally part of the exercitus praesentales (imperial escort armies); comitatenses

Comitatenses

Comitatenses is the Latin plural of comitatensis, originally the adjective derived from comitatus , itself rooting in Comes .However, historically it became the accepted name for...

, higher-grade interception forces based in frontier provinces; and limitanei

Limitanei

The limitanei, meaning "the soldiers in frontier districts" The limitanei, meaning "the soldiers in frontier districts" The limitanei, meaning "the soldiers in frontier districts" (from the Latin phrase limes, denoting the military districts of the frontier provinces established in the late third...

, lower-grade border troops. (See Late Roman army

Late Roman army

The Late Roman army is the term used to denote the military forces of the Roman Empire from the accession of Emperor Diocletian in 284 until the Empire's definitive division into Eastern and Western halves in 395. A few decades afterwards, the Western army disintegrated as the Western empire...

).

The old Principate auxilia regiments provided the basis for units at all three grades. The Notitia Dignitatum lists about 70 alae and cohortes that retained their 2nd century names, mostly limitanei. But traces of other auxilia regiments can be found in the praesentales and comitatenses armies. For example, many of the new-style auxilia palatina

Auxilia palatina

Auxilia palatina were infantry units of the Late Roman army, first raised by Constantine I as part of the new field army he created in about 325....

infantry regiments, considered among the best units in the army, were probably formed from old-style auxiliary cohortes, which they appear to closely resemble.

The late 4th century writer on military affairs Vegetius complains of contemporary young men joining the "auxilia" in preference to the "legions" to avoid the latter's tougher training and duties. But it is unclear what types of units he was referring to. It is possible that those older terms were still popularly used (misleadingly) to mean limitanei and comitatenses respectively. In any event, his quote in no way describes accurately the Principate auxilia, many of which were of very high quality.

Regular unit types

The following table sets out the official, or establishment, strength of auxiliary units in the 2nd century. The real strength of a unit would fluctuate continually, but would likely have been somewhat less than the establishment most of the time.

ROMAN AUXILIARY REGIMENTS: TYPE, STRUCTURE AND STRENGTH
! Unit type !! Service !! Unit
commander !! Sub-unit
commander !! No of
sub-units !! Sub-unit
strength !! Unit
strength

Ala Ala (Roman military) An Ala was the term used during the mid- Roman Republic to denote a military formation composed of conscripts from the socii, Rome's Italian military allies. A normal consular army during this period consisted of 2 legions, composed of Roman citizens only, and 2 allied alae...  quingenaria	cavalry	praefectus	decurio Decurio Decurio was an official title in Ancient Rome, used in various connections:# A member of the senatorial order in the Italian towns under the administration of Rome, and later in provincial towns organized on the Italian model . The number of decuriones varied in different towns, but was usually 100...	16 turmae	30 (32)	480 (512)
Ala Ala (Roman military) An Ala was the term used during the mid- Roman Republic to denote a military formation composed of conscripts from the socii, Rome's Italian military allies. A normal consular army during this period consisted of 2 legions, composed of Roman citizens only, and 2 allied alae...  milliaria	cavalry	praefectus	decurio	24 turmae	30 (32)	720 (768)
Cohors quingenaria	infantry	praefectus*	centurio Centurion A centurion was a professional officer of the Roman army .Centurion may also refer to:-Military:* Centurion tank, British battle tank* HMS Centurion, name of several ships and a shore base of the British Royal Navy...	6 centuriae	80	480
Cohors milliaria	infantry	tribunus militum Tribune Tribune was a title shared by elected officials in the Roman Republic. Tribunes had the power to convene the Plebeian Council and to act as its president, which also gave them the right to propose legislation before it. They were sacrosanct, in the sense that any assault on their person was... **	centurio	10 centuriae	80	800
Cohors equitata quingenaria	infantry plus cavalry contingent	praefectus	centurio (inf) decurio (cav)	6 centuriae 4 turmae	80 30.	600 (480 inf/120 cav)
Cohors equitata milliaria	infantry plus cavalry contingent	tribunus militum**	centurio (inf) decurio (cav)	10 centuriae 8 turmae	80 30	1,040 (800 inf/240 cav)

* tribunus militum in original c.R. cohortes

• • praefectus in Batavi and Tungri cohortes milliariae

NOTE: Opinion is divided about the size of an ala turma, between 30 and 32 men. 30 was the size of a turma in the Republican cavalry and in the cohors equitata of the Principate auxilia. Against this is a statement by Arrian

Arrian

Lucius Flavius Arrianus 'Xenophon , known in English as Arrian , and Arrian of Nicomedia, was a Roman historian, public servant, a military commander and a philosopher of the 2nd-century Roman period...

 that an ala was 512 strong. This would make an ala turma 32 men strong.

Cohortes

These all-infantry units were modelled on the cohorts of the legions, with the same officers and sub-units. It is a common misconception that auxiliary cohortes contained light infantry. Their defensive equipment was very similar to that of legionaries, consisting of metal helmet and metal cuirass (chain-mail or scale). Some auxiliaries were also equipped with the lorica segmentata

Lorica segmentata

The lōrīca segmentāta was a type of segmented armour almost exclusively used in the Roman Empire, but the Latin name was first used in the 16th century...

, the standard but not exclusive legionary's body-armor.
There is no evidence that auxiliary infantry fought in a looser order than legionaries. It appears that in a set-piece battle-line, auxiliary infantry would normally be stationed on the flanks, with legionary infantry holding the centre e.g. as in the Battle of Watling Street

Battle of Watling Street

The Battle of Watling Street took place in Roman-occupied Britain in AD 60 or 61 between an alliance of indigenous British peoples led by Boudica and a Roman army led by Gaius Suetonius Paulinus. Although outnumbered, the Romans decisively defeated the allied tribes, inflicting heavy losses on them...

 (60 CE), the final defeat of the rebel Britons under queen Boudicca

Boudica

Boudica , also known as Boadicea and known in Welsh as "Buddug" was queen of the British Iceni tribe who led an uprising against the occupying forces of the Roman Empire....

. This was a tradition inherited from the Republic, when the precursors of auxiliary cohortes, the Latin alae, occupied the same position in the line. The flanks of the line required equal, if not greater, skill to hold as the centre.

Alae

During the Principate

Principate

The Principate is the first period of the Roman Empire, extending from the beginning of the reign of Caesar Augustus to the Crisis of the Third Century, after which it was replaced with the Dominate. The Principate is characterized by a concerted effort on the part of the Emperors to preserve the...

 period of the Roman Empire

Roman Empire

The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

 (30 BC - AD 284), the all-mounted alae contained the elite cavalry of the army. They were specially trained in elaborate manoeuvres, such as those displayed to the emperor Hadrian during a documented inspection. They were best-suited for large-scale operations and battle, during which they acted as the primary cavalry escort for the legions, which had almost no cavalry of their own. They were heavily protected, with chain-mail or scale body armour, a cavalry version of the infantry helmet (with more protective features) and oval shield. Their offensive weapons included a spear (hasta

Hasta (spear)

Hasta is a Latin word meaning spear. Hastae were carried by early Roman Legionaries, in particular they were carried by and gave their name to those Roman soldiers known as Hastati...

), a cavalry sword (spatha

Spatha

The spatha was a type of straight sword, measuring between , in use throughout first millennium AD Europe, and in the territory of the Roman Empire until about 600 AD. Later swords from 600 AD to 1000 AD are recognizable derivatives, though they are not spathae.The spatha was used in gladiatorial...

), which was much longer than the infantry gladius to provide greater reach and a long dagger. The elite status of an alaris is shown by the fact that he received 20% greater pay than his counterpart in a cohort, and than a legionary infantryman.

Cohortes equitatae

These were cohortes with a cavalry contingent attached. There is evidence that their numbers expanded with the passage of time. Only about 40% of attested cohortes are specifically attested as equitatae in inscriptions, which is probably the original Augustan proportion. A study of units stationed in Syria in the mid 2nd century found that many units which did not carry the equitata title did in fact contain cavalrymen e.g. by discovery of a tombstone of a cavalryman attached to the cohort. This implies that by that time, at least 70% of cohortes were probably equitatae. The addition of cavalry to a cohort obviously enabled it to carry out a wider range of independent operations. A cohors equitata was in effect a self-contained mini-army.

The traditional view of equites cohortales (the cavalry arm of cohortes equitatae), as expounded by G.L. Cheesman, was that they were just a mounted infantry with poor-quality horses. They would use their mounts simply to reach the battlefield and then would dismount to fight. This view is today discredited. Although it is clear that equites cohortales did not match equites alares (ala cavalrymen) in quality (hence their lower pay), the evidence is that they fought as cavalry in the same way as the alares and often alongside them. Their armour and weapons were the same as for the alares.

Nevertheless, non-combat roles of the equites cohortales differed significantly from the alares. Non-combat roles such as despatch-riders (dispositi) were generally filled by cohort cavalry.

Auxiliary specialised units

In the Republican period, the standard trio of specialised auxilia were Balearic slingers, Cretan archers and Numidian light cavalry. These functions, plus some new ones, continued in the 2nd century auxilia.

Heavily-armoured lancers

Equites cataphractarii

Equites cataphractarii

Equites cataphractarii, or simply cataphractarii for short, were the heavily-armoured cavalry of the Imperial Roman army.Modelled on the cataphracts of Parthia, they were covered from neck-to-toe by lamellar armour , and normally armed with a contus, a long lance held in both hands, although...

, or simply cataphractarii for short, were the heavily-armoured cavalry of the Roman army

Roman army

The Roman army is the generic term for the terrestrial armed forces deployed by the kingdom of Rome , the Roman Republic , the Roman Empire and its successor, the Byzantine empire...

. Based on Sarmatian

Sarmatians

The Iron Age Sarmatians were an Iranian people in Classical Antiquity, flourishing from about the 5th century BC to the 4th century AD....

 and Parthia

Parthia

Parthia is a region of north-eastern Iran, best known for having been the political and cultural base of the Arsacid dynasty, rulers of the Parthian Empire....

n models, they were also known as contarii and clibanarii

Clibanarii

The Clibanarii or Klibanophoroi were a Sassanid Persian, late Roman and Byzantine military unit of heavy armored horsemen. Similar to the cataphracti, the horsemen themselves and their horses were fully armoured...

, although it is unclear whether these terms were interchangeable or whether they denoted variations in equipment or role. Together with new units of light mounted archers, the cataphractarii were designed to counter Parthian (and, in Pannonia

Pannonia

Pannonia was an ancient province of the Roman Empire bounded north and east by the Danube, coterminous westward with Noricum and upper Italy, and southward with Dalmatia and upper Moesia....

, Sarmatian) battle tactics. Parthian armies consisted largely of cavalry. Their standard tactic was to use light mounted archers to weaken and break up the Roman infantry line, and then to rout it with a charge by the cataphractarii concentrated on the weakest point. The only special heavy cavalry units to appear in the 2nd century record are: ala I Ulpia contariorum and ala I Gallorum et Pannoniorum cataphractaria stationed in Pannonia and Moesia Inferior respectively in the 2nd century.

Light cavalry

From the Second Punic War until the 3rd century AD, the bulk of Rome's light cavalry (apart from mounted archers from Syria) was provided by the inhabitants of the northwest African provinces of Africa proconsularis and Mauretania

Mauretania Caesariensis

Mauretania Caesariensis was a Roman province located in northwestern Africa. It was the easternmost of the North African Roman provinces, mainly in present Algeria, with its capital at Caesarea , now Cherchell.-Historical background:In the first century AD, Roman...

, the Numidae or Mauri (from whom derives the English term "Moors"), who were the ancestors of the Berber

Berber mythology

The traditional Berber mythology is the ancient and native set of beliefs and deities developed by the Berber people in their historical land of North Africa...

 people of modern Algeria

Algeria

Algeria , officially the People's Democratic Republic of Algeria , also formally referred to as the Democratic and Popular Republic of Algeria, is a country in the Maghreb region of Northwest Africa with Algiers as its capital.In terms of land area, it is the largest country in Africa and the Arab...

 and Morocco

Morocco

Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...

. They were known as the equites Maurorum or Numidarum ("Moorish or Numidian cavalry

Numidian cavalry

Numidian cavalry was a type of light cavalry developed by the Numidians, most notably used by Hannibal during the Second Punic War. They were described by the Roman historian Livy as "by far the best horsemen in Africa."...

"). On Trajan's Column, Mauri horsemen, depicted with long hair in dreadlocks, are shown riding their small but resilient horses bare-back and unbridled, with a simple braided rope round their mount's neck for control. They wear no body or head armour, carrying only a small, round leather shield. Their weaponry cannot be discerned due to stone erosion, but is known from Livy to have consisted of several short javelins. Exceptionally fast and maneouvrable, Numidian cavalry would harass the enemy by hit-and-run attacks, riding up and loosing volleys of javelins, then scattering faster than any opposing cavalry could pursue. They were superbly suited to scouting, harassment, ambush and pursuit. It is unclear what proportion of the Numidian cavalry were regular auxilia units as opposed to irregular foederati units.

In the 3rd century, new formations of light cavalry appear, apparently recruited from the Danubian provinces: the equites Dalmatae ("Dalmatian cavalry"). Little is known about these, but they were prominent in the 4th century, with several units listed in the Notitia Dignitatum.

Camel troops

A unit of dromedarii ("camel-mounted troops") is attested from the 2nd century, the ala I Ulpia dromedariorum milliaria in Syria.

Archers

A substantial number of auxiliary regiments (32, or about 1 in 12 in the 2nd century) were denoted sagittariorum, or archer-units (from sagittarii

Sagittarii

Sagittarii Sagitarii is the latin term for archers. The term sagittariorum in the title of an infantry or cavalry unit indicated a specialized archer regiment. Regular auxiliary units of foot and horse archers appeared in the Roman army during the early empire...

lit. "arrow-men", from sagitta = "arrow"). These 32 units (of which 4 were double-strength) had a total official strength of 17,600 men. All three types of auxiliary regiment (ala, cohors and cohors equitata) could be denoted sagittariorum. Although these units evidently specialised in archery, it is uncertain from the available evidence whether all sagittariorum personnel were archers, or simply a higher proportion than in ordinary units. At the same time, ordinary regiments probably also possessed some archers, otherwise their capacity for independent operations would have been unduly constrained. Bas-reliefs appear to show personnel in ordinary units employing bows.

From about 218 BC onwards, the archers of the Roman army of the mid-Republic

Roman army of the mid-Republic

The Roman army of the mid-Republic , refers to the armed forces deployed by the mid- Roman Republic The Roman army of the mid-Republic (also known as the manipular Roman army or the "Polybian army"), refers to the armed forces deployed by the mid- Roman Republic The Roman army of the mid-Republic...

 were virtually all mercenaries from the island of Crete

Crete

Crete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...

, which boasted a long specialist tradition. During the late Republic (88-30 BC) and the Augustan period, Crete was gradually eclipsed by men from other, much more populous, regions subjugated by the Romans with strong archery traditions. These included Thrace

Thrace

Thrace is a historical and geographic area in southeast Europe. As a geographical concept, Thrace designates a region bounded by the Balkan Mountains on the north, Rhodope Mountains and the Aegean Sea on the south, and by the Black Sea and the Sea of Marmara on the east...

, Anatolia

Anatolia

Anatolia is a geographic and historical term denoting the westernmost protrusion of Asia, comprising the majority of the Republic of Turkey...

 and above all, Syria

Syria

Syria , officially the Syrian Arab Republic , is a country in Western Asia, bordering Lebanon and the Mediterranean Sea to the West, Turkey to the north, Iraq to the east, Jordan to the south, and Israel to the southwest....

. Of the 32 sagittarii units attested in mid 2nd century, 13 have Syrian names, 7 Thracian, 5 from Anatolia, 1 from Crete and the remaining 6 of other or uncertain origin.

Three distinct types of archers are shown on Trajan's Column: (a) with scalar cuirass, conical steel helmet and cloak; (b) without armour, with cloth conical cap and long tunic; or (c) equipped in the same way as general auxiliary foot-soldiers (apart from carrying bows instead of javelins). The first type were probably Syrian or Anatolian units; the third type probably Thracian. The standard bow used by Roman auxilia was the recurved composite bow

Composite bow

A composite bow is a bow made from horn, wood, and sinew laminated together. The horn is on the belly, facing the archer, and sinew on the back of a wooden core. Sinew and horn will store more energy than wood for the same length of bow...

, a sophisticated, compact and powerful weapon.

Slingers

From about 218 BC onwards, the Republican army's slingers were exclusively mercenaries from the Balearic Islands

Balearic Islands

The Balearic Islands are an archipelago of Spain in the western Mediterranean Sea, near the eastern coast of the Iberian Peninsula.The four largest islands are: Majorca, Minorca, Ibiza and Formentera. The archipelago forms an autonomous community and a province of Spain with Palma as the capital...

, which had nurtured a strong indigenous tradition of slinging from prehistoric times. As a result, in classical Latin, Baleares (literally "inhabitants of the Balearic Islands") became an alternative word for "slingers" (funditores, from funda = "sling"). Because of this, it is uncertain whether the most of the imperial army's slingers continued to be drawn from the Balearics themselves, or, like archers, derived mainly from other regions.

Independent slinger units are not attested in the epigraphic record of the Principate. However, slingers are portrayed on Trajan's Column. They are shown unarmoured, wearing a short tunic. They carry a cloth bag, slung in front, to hold their shot (glandes).

Scouts

Exploratores ("reconnaissance troops", from explorare = "to scout"): Examples include two numeri exploratorum attested in the 3rd century in Britain: Habitanco and Bremenio (both names of forts). Little is known about such units.

Irregular allied forces

Throughout the Principate period, there is evidence of ethnic units of barbari outside the normal auxilia organisation fighting alongside Roman troops. To an extent, these units were simply a continuation of the old client-king levies of the late Republic: ad hoc bodies of troops supplied by Rome's puppet petty-kings on the imperial borders for particular campaigns. Some clearly remained in Roman service beyond the campaigns, keeping their own native leadership, attire and equipment and structure. These units were known to the Romans as socii ("allies"), symmachiarii (from symmachoi, Greek for "allies") or foederati

Foederati

Foederatus is a Latin term whose definition and usage drifted in the time between the early Roman Republic and the end of the Western Roman Empire...

("treaty troops" from foedus, "treaty"). One estimate puts the number of foederati in the time of Trajan at about 11,000, divided into about 40 numeri (units) of about 300 men each. The purpose of employing foederati units was to use their specialist fighting skills. Many of these would have been troops of Numidian cavalry (see light cavalry above).

The foederati make their first official appearance on Trajan's Column, where they are portrayed in a standardised manner, with long hair and beards, barefoot, stripped to the waist, wearing long trousers held up by wide belts and wielding clubs. In reality several different tribes supported the Romans in the Dacian wars. Their attire and weapons would have varied widely. The Column stereotypes them with the appearance of a single tribe, probably the most outlandish-looking, to differentiate them clearly from the regular auxilia. Judging by the frequency of their appearance in the Column's battle scenes, the foederati were important contributors to the Roman operations in Dacia. Another example of foederati are the 5,500 captured Sarmatian cavalrymen sent by Emperor Marcus Aurelius (r. 161–180) to garrison a fort on Hadrian's Wall after their defeat in the Marcomannic Wars

Marcomannic Wars

The Marcomannic Wars were a series of wars lasting over a dozen years from about AD 166 until 180. These wars pitted the Roman Empire against the Marcomanni, Quadi and other Germanic peoples, along both sides of the upper and middle Danube...

.

Recruitment, ranks and pay

The evidence for auxiliary ranks and pay is scant, even less than the patchy evidence for their legionary counterparts. The available data may be summarised as follows:

AUXILIA RANKS AND PAY (mid 1st century)
! Pay scale
(as multiple of basic) !! Cohors infantry rank
(in ascending order) !! Amount
(denarii) !! XXX !! Ala rank
(in ascending order) !! Amount
(denarii)

1 (caligati = "rankers")	pedes (infantryman)	188		gregalis (ala cavalryman)	263
1.5 (sesquiplicarii = "one-and-half-pay men")	tesserarius (corporal)	282		sesquiplicarius (corporal)	395
2 (duplicarii = "double-pay men")	signifer (centuria standard-bearer) optio (centurion's deputy) vexillarius (cohort standard-bearer)	376		signifer (turma standard-bearer) curator? (decurion's deputy) vexillarius (ala standard-bearer)	526
Over 5	centurio (centurion = centuria commander) centurio princeps (chief centurion) beneficiarius? (deputy cohort commander)	940 +		decurio (decurion = turma commander) decurio princeps (chief decurion) beneficiarius? (deputy ala commander)	1,315 +
50	praefectus or tribunus (cohort commander)	9,400		praefectus or tribunus (ala commander)	13,150

Common soldiers (caligati)

At the bottom end of the rank pyramid, rankers were known as caligati (lit: "sandal men" from the caligae or hob-nailed sandals worn by soldiers). Depending on the type of regiment they belonged to, they held the official ranks of pedes (foot soldier in a cohors), eques (cavalryman in a cohors equitata) and gregalis (ala cavalryman).

During the Principate, recruitment into the legions was restricted to Roman citizens only. This rule, which derived from the pre-Social War Republican army, was strictly enforced. The few exceptions recorded, such as during emergencies and for the illegitimate sons of legionaries, do not warrant the suggestion that the rule was routinely ignored.

In the 1st century, the vast majority of auxiliary common soldiers were recruited from the Roman peregrini (second-class citizen

Second-class citizen

Second-class citizen is an informal term used to describe a person who is systematically discriminated against within a state or other political jurisdiction, despite their nominal status as a citizen or legal resident there...

s). In the Julio-Claudian era, conscription

Conscription

Conscription is the compulsory enlistment of people in some sort of national service, most often military service. Conscription dates back to antiquity and continues in some countries to the present day under various names...

 of peregrini seems to have been practiced alongside voluntary recruitment, probably in the form of a fixed proportion of men reaching military age in each tribe being drafted. From the Flavian era onwards, the auxilia were an all-volunteer force. Although recruits as young as 14 are recorded, the majority of recruits (66%) were from the 18–23 age group.

When it was first raised, an auxiliary regiment would have been recruited from the native tribe or people whose name it bore. In the early Julio-Claudian period, it seems that efforts were made to preserve the ethnic integrity of units, even when the regiment was posted in a faraway province. But in the later part of the period, recruitment in the region where the regiment was posted increased and became predominant from the Flavian era onwards. The regiment would thus lose its original ethnic identity. The unit's name would thus become a mere curiosity devoid of meaning, although some of its members might inherit foreign names from their veteran ancestors. This view has to be qualified, however, as evidence from military diplomas and other inscriptions shows that some units continued to recruit in their original home areas e.g. Batavi units stationed in Britain, where some units had an international membership. It also appears that the Danubian provinces (Raetia, Pannonia, Moesia, Dacia) remained key recruiting grounds for units stationed all over the empire.

It appears that Roman citizens were also regularly recruited to the auxilia. Most likely, the majority of citizen recruits to auxiliary regiments were the sons of auxiliary veterans who were enfranchised on their fathers' discharge. Many such may have preferred to join their fathers' old regiments, which were a kind of extended family to them, rather than join a much larger, unfamiliar legion. There are also instances of legionaries transferring to the auxilia (to a higher rank). The incidence of citizens in the auxilia would thus have grown steadily over time until, after the grant of citizenship to all peregrini in 212, auxiliary regiments became predominantly, if not exclusively, citizen units.

Less clearcut is the question of whether the regular auxilia recruited barbari (barbarians, as the Romans called people living outside the empire's borders). Although there is little evidence of it before the 3rd century, the consensus is that auxilia recruited barbarians throughout their history. In the 3rd century, a few auxilia units of clearly barbarian origin start to appear in the record e.g. Ala I Sarmatarum, cuneus Frisiorum and numerus Hnaufridi in Britain.

There existed a hierarchy of pay between types of auxiliary, with cavalry higher paid than infantry. One recent estimate is that in the time of Augustus, the annual pay structure was: eques alaris (gregalis) 263 denarii, eques cohortalis 225, and cohors infantryman 188. The same differentials (of about 20% between grades) seem to have existed at the time of Domitian (r. 81-96). However, Goldsworthy points out that the common assumption that rates of pay were universal across provinces and units is unproven. Pay may have varied according to the origin of the unit.

The remuneration of an auxiliary pedes cohortalis may be compared to a legionary's as follows:

REMUNERATION OF ROMAN COMMON FOOT SOLDIERS (about AD 70)

Remuneration item	legionary pedes: amount (denarii) (annualised)	XXX	auxiliary pedes amount (denarii) (annualised)
Stipendium (gross salary)	225		188
Less: Food deduction	60		60
Less: Equipment etc. deductions	50		50
Net disposable pay	115		78
Plus: Donativa (bonuses) (average: 75 denarii every 3 years)	25		none proven
Total disposable income	140		78
Praemia (discharge bonus: 3,000 denarii)	120		none proven

Gross salary was subject to deductions for food, clothing, boots and hay (probably for the company mules). It is unclear whether the cost of armour and weapons was also deducted, or borne by the army. Deductions left the soldier with a net salary of 78 denarii. This sum was sufficient, on the basis of the food deduction, to amply feed an adult for a year. In 84 AD Domitian

Domitian

Domitian was Roman Emperor from 81 to 96. Domitian was the third and last emperor of the Flavian dynasty.Domitian's youth and early career were largely spent in the shadow of his brother Titus, who gained military renown during the First Jewish-Roman War...

 increased basic legionary pay by 33% (from 225 to 300 denarii): a similar increase was presumably accorded to auxiliaries, boosting their net income to 140 denarii, i.e. more than two food allowances. It was entirely disposable, as the soldier was exempt from the poll tax

Poll tax

A poll tax is a tax of a portioned, fixed amount per individual in accordance with the census . When a corvée is commuted for cash payment, in effect it becomes a poll tax...

 (capitatio), did not pay rent (he was housed in fort barracks) and his food, clothing and equipment were already deducted. It should be borne in mind that most recruits came from peasant families living at subsistence level

Subsistence agriculture

Subsistence agriculture is self-sufficiency farming in which the farmers focus on growing enough food to feed their families. The typical subsistence farm has a range of crops and animals needed by the family to eat and clothe themselves during the year. Planting decisions are made with an eye...

. To such persons, any disposable income would appear attractive. It could be spent on leisure activities, sent to relatives or simply saved for retirement.

There is no evidence that auxiliaries received the substantial cash bonuses (donativum

Donativum

Donativum was the name given to the gifts of money dispersed to the soldiers of the Roman legions or to the Praetorian Guard by the Roman Emperors....

) handed to legionaries on the accession of a new emperor and other occasions. Although irregular, these payments (each worth 75 denarii to a common legionary) averaged once every 7.5 years in the early 1st century and every three years later. Duncan-Jones has suggested that donativa may have been paid to auxiliaries also from the time of Hadrian onwards, on the grounds that the total amount of donative to the military increased sharply at that time. A very valuable benefit paid to legionaries was the discharge bonus (praemia) paid on completion of the full 25 years' service. At 3,000 denarii, this was equivalent to ten years' gross salary for a common legionary after the pay increase of 84 AD. It would enable him to purchase a substantial plot of land. Again, there is no indication that auxiliaries were paid a discharge bonus. For auxiliaries, the discharge bonus was the grant of Roman citizenship, which carried important tax exemptions. However, Duncan-Jones argues that the fact that service in the auxilia was competitive with the legions (deduced from the many Roman citizens that joined the auxilia) that a discharge bonus may have been paid.

Junior officers (principales)

Below centurion/decurion rank, junior officers in the Roman army were known as principales. An auxiliary cohort's ranks appear the same as in a legionary centuria. These were, in ascending order: tesserarius ("officer of the watch"), signifer (standard-bearer for the centuria), optio (centurion's deputy) and vexillarius (standard-bearer for the whole regiment, from vexillum

Vexillum

The vexillum was a flag-like object used in the Classical Era of the Roman Empire. The word is itself a diminutive for the Latin word, velum, sail, which confirms the historical evidence that vexilla were literally "little sails" i.e. flag-like standards...

). In the turmae of cohortes equitatae (and of alae?), the decurion's second-in-command was probably known as a curator, responsible for horses and caparison. As in the legions, the principales, together with some regimental specialists, were classified in two pay-scales: sesquiplicarii ("one-and-a-half-pay men") and duplicarii ("double-pay men"). These ranks are probably most closely resembled by the modern ranks of corporal

Corporal

Corporal is a rank in use in some form by most militaries and by some police forces or other uniformed organizations. It is usually equivalent to NATO Rank Code OR-4....

 and sergeant

Sergeant

Sergeant is a rank used in some form by most militaries, police forces, and other uniformed organizations around the world. Its origins are the Latin serviens, "one who serves", through the French term Sergent....

 respectively.

Besides combat effectives, regiments also contained specialists, the most senior of whom were sesquiplicarii or duplicarii, the rest common soldiers with the status of milities immunes ("exempt soldiers" i.e. exempt from normal duties). Ranking specialists included the medicus (regimental doctor), veterinarius (veterinary doctor, in charge of the care of horses, pack animals and livestock), custos armorum (keeper of the armoury), and the cornicularius (clerk in charge of all the regiment's records and paperwork).

Senior officers

The limited evidence on auxiliary centuriones and decuriones is that such officers could be directly commissioned as well as promoted from the ranks. Many appear to have come from provincial aristocracies. Those rising from the ranks could be promotions from the legions as well as from the regiment's own ranks. In the Julio-Claudian period auxiliary centuriones and decuriones were a roughly equal split between citizens and peregrini, though later citizens became predominant due to the spread of citizenship among military families. Because centuriones and decuriones could rise from the ranks, they have often been compared to non-commissioned officers such as sergeants in modern armies. But this comparison certainly undervalues their role and social status. In addition to their military duties, centurions performed a wide range of administrative tasks, which was necessary in the absence of an adequate bureaucracy to support provincial governors. They were also relatively wealthy, due to their high salaries (see table above). A mid-level modern officer such as a major

Major

Major is a rank of commissioned officer, with corresponding ranks existing in almost every military in the world.When used unhyphenated, in conjunction with no other indicator of rank, the term refers to the rank just senior to that of an Army captain and just below the rank of lieutenant colonel. ...

 is probably a closer parallel. However, most of the surviving evidence concerns legionary centurions and it is uncertain whether their auxiliary counterparts shared their high status and non-military role.

There is little evidence about the pay-scales of auxiliary centuriones and decuriones, but these are also believed to have amounted to several times that of a miles.

Unlike a legatus legionis

Legatus legionis

Legatus legionis was a title awarded to legion commanders in Ancient Rome.-History:By the time of the Roman Republic, the term legatus delegated authority...

(who had an officer staff of 6 tribuni militum and one praefectus castrorum), an auxiliary praefectus does not appear to have enjoyed the support of purely staff officers. The possible exception is an attested beneficiarius ("deputy"), who may have been the praefectus' second-in-command, if this title was a regular rank and not simply an ad hoc appointment for a specific task. Also attached to the praefectus were the regiment's vexillarius (standard-bearer for the whole unit) and cornucen (horn-blower).

Commanders

It appears that in the 2nd century, the majority of auxiliary prefects were still of Italian origin. In contrast, the evidence for the 3rd century is that Italians provided less than a third of prefects. All prefects were members of the equestrian order, either by birth, or by attaining the property qualification (100,000 denarii, the equivalent of 400 years' gross salary for an auxiliary alaris) or by military promotion. The latter were the chief centurions of legions (centurio primus pilus) who would normally be elevated to equestrian rank by the emperor after completing their single-year term as primuspilus.

Equestrians by birth would normally begin their military careers at ca. 30 years of age. Commands were held in a set sequence, each held for 3–4 years: prefect of an auxiliary cohors, tribunus militum in a legion and finally prefect of an auxiliary ala. In Hadrian's time, a fourth command was added, for exceptionally able officers, of prefect of an ala milliaria. Like officers senatorial rank, hereditary equestrians held civilian posts before and after their decade of military service, whereas non-hereditary officers tended to remain in the army, commanding various units in various provinces. By the 3rd century, most auxiliary prefects had exclusively military careers.

The pay of a praefectus of an auxiliary regiment in the early 2nd century has been estimated at over 50 times that of a miles (common soldier). (This compares to a full colonel

Colonel

Colonel , abbreviated Col or COL, is a military rank of a senior commissioned officer. It or a corresponding rank exists in most armies and in many air forces; the naval equivalent rank is generally "Captain". It is also used in some police forces and other paramilitary rank structures...

 in the British Army, who is currently paid about five times a private's salary). The reason for the huge gap between the top and the bottom of the pyramid is that Roman society was far more hierarchical than a modern one. A praefectus was not just a senior officer. He was also a Roman citizen (which most of his men were not) and, as a member of the equestrian order, an aristocrat. The social gulf between the praefectus and a peregrinus soldier was thus immense, and the pay differential reflected that fact.

Regimental names

The nomenclature of the great majority of regiments followed a standard configuration: unit type, followed by serial number, followed by name of the peregrini tribe (or nation) from whom the regiment was originally raised, in the genitive plural case e.g. cohors III Batavorum ("3rd Cohort of Batavi"); cohors I Brittonum ("1st Cohort of Britons"). Some regiments combine the names of two peregrini tribes, most likely after the merger of two previously separate regiments e.g. ala I Pannoniorum et Gallorum ("1st Wing of Pannonii and Gauls"). A minority of regiments are named after an individual, mostly after the first prefect of the regiment e.g. ala Sulpicia (presumably named after a prefect whose middle (gens) name was Sulpicius). The latter is also an example of regiments that did not have a serial number.

Titles

Regiments were often rewarded for meritorious service by the grant of an honorific title. The most sought-after was the prestigious c.R. (civium Romanorum = "of Roman citizens") title. In the latter case, all the regiment's members at the time, but not their successors, would be granted Roman citizenship. But the regiment would retain the c.R. title in perpetuity. Another common title was the gens name of the emperor making the award (or founding the regiment) e.g. Ulpia: the gens name of Trajan

Trajan

Trajan , was Roman Emperor from 98 to 117 AD. Born into a non-patrician family in the province of Hispania Baetica, in Spain Trajan rose to prominence during the reign of emperor Domitian. Serving as a legatus legionis in Hispania Tarraconensis, in Spain, in 89 Trajan supported the emperor against...

 (Marcus Ulpius Traianus r.98–117). Other titles were similar to those given to the legions e.g. pia fidelis (p.f. = "dutiful and loyal").

Decorations

The Roman army awarded a variety of individual decorations (dona) for valour to its legionaries. Hasta pura was a miniature spear; phalerae were large medal-like bronze or silver discs worn on the cuirass; armillae were bracelets worn on the wrist; and torques

Torc

A torc, also spelled torq or torque, is a large, usually rigid, neck ring typically made from strands of metal twisted together. The great majority are open-ended at the front, although many seem designed for near-permanent wear and would have been difficult to remove. Smaller torcs worn around...

 were worn round the neck, or on the cuirass. The highest awards were the coronae ("crowns"), of which the most prestigious was the corona civica, a crown made oak-leaves awarded for saving the life of a Roman citizen in battle. The most valuable award was the corona muralis, a crown made of gold awarded to the first man to scale an enemy rampart. This was awarded rarely, as such a man hardly ever survived.

There is no evidence that auxiliary common soldiers received individual decorations, although auxiliary officers did. Instead, the whole regiment was honoured by a title reflecting the type of award e.g. torquata (awarded a torque) or armillata (awarded bracelets). Some regiments would, in the course of time, accumulate a long list of titles and decorations e.g. cohors I Brittonum Ulpia torquata pia fidelis c.R..

Deployment in 2nd century

IMPERIAL AUXILIA: Summary of known deployments c. 130 AD
! Province !! Approx. modern
equivalent !! Alae
(no. mill.) !! Cohortes
(no. mill.) !! Total
aux. units !! Auxiliary
infantry !! Auxiliary
cavalry* !! Total
auxilia

Britannia	England/Wales	11 (1)	45 (6)	56	25,520	10,688	36,208
Rhine Frontier
Germania Inferior	S Neth/NW Rhineland	6	17	23	8,160	4,512	12,672
Germania Superior	Pfalz/Alsace	3	22 (1)	25	10,880	3,336	14,216
Danube Frontier
Raetia/Noricum	S Ger/Switz/Austria	7 (1)	20 (5)	27	11,220	5,280	16,500
Pannonia (Inf + Sup)	W Hungary/Slovenia	11 (2)	21 (4)	32	11,360	8,304	19,664
Moesia Superior	Serbia	2	10	12	4,800	1,864	6,664
Moesia Inferior	N Bulgaria/coastal Rom	5	12	17	5,760	3,520	9,280
Dacia (Inf/Sup/Poroliss)	Romania	11 (1)	32 (8)	43	17,920	7,328	25,248
Eastern Frontier
Cappadocia	Central/East Turkey	4	15 (2)	19	7,840	3,368	11,208
Syria (inc Judaea/Arabia)	Syria/Leb/Palest/Jordan/Israel	12 (1)	43 (3)	55	21,600	10,240	31,840
North Africa
Aegyptus	Egypt	4	11	15	5,280	3,008	8,288
Mauretania (inc Africa)	Tunisia/Algeria/Morocco	10 (1)	30 (1)	40	14,720	7,796	22,516
Internal provinces		2	15	17	7,200	2,224	9,424
TOTAL EMPIRE		88 (7)	293 (30)	381	152,260	71,468	223,728

Analysis

1. The table shows the importance of auxiliary troops in the 2nd century, when they outnumbered legionaries by 1.5 to 1.
2. The table shows that legions did not have a standard complement of auxiliary regiments and that there was no fixed ratio of auxiliary regiments to legions in each province. The ratio varied from six regiments per legion in Cappadocia to 40 per legion in Mauretania.
3. Overall, cavalry represented about 20% (including the small contingents of legionary cavalry) of the total army effectives. But there were variations: in Mauretania the cavalry proportion was 28%.
4. The figures show the massive deployments in Britannia and Dacia. Together, these two provinces account for 27% of the total auxilia corps.

See also

• Roman Army
  Roman army
  The Roman army is the generic term for the terrestrial armed forces deployed by the kingdom of Rome , the Roman Republic , the Roman Empire and its successor, the Byzantine empire...
  
  
• Imperial Roman army
  Imperial Roman army
  The Imperial Roman army refers to the armed forces deployed by the Roman Empire during the Principate era .Under the founder–emperor Augustus , the legions, which were formations numbering about 5,000 heavy infantry recruited from Roman citizens only, were transformed from a mixed conscript and...
  
  
• List of Roman auxiliary regiments
• Structural History of the Roman military
  Structural history of the Roman military
  The structural history of the Roman military concerns the major transformations in the organization and constitution of ancient Rome's armed forces, "the most effective and long-lived military institution known to history." From its origins around 800 BC to its final dissolution in AD 476...
  
  
• Auxiliaries in Britain (Roman military)

Ancient

• Arrian
  Arrian
  Lucius Flavius Arrianus 'Xenophon , known in English as Arrian , and Arrian of Nicomedia, was a Roman historian, public servant, a military commander and a philosopher of the 2nd-century Roman period...
  
   Acies contra Alanos (early 2nd c.)
• Dio Cassius
  Dio Cassius
  Lucius Cassius Dio Cocceianus , known in English as Cassius Dio, Dio Cassius, or Dio was a Roman consul and a noted historian writing in Greek...
  
   Roman History (mid 3rd c.)
• Suetonius
  Suetonius
  Gaius Suetonius Tranquillus, commonly known as Suetonius , was a Roman historian belonging to the equestrian order in the early Imperial era....
  
   De vita Caesarum (early 2nd c.)
• Tacitus
  Tacitus
  Publius Cornelius Tacitus was a senator and a historian of the Roman Empire. The surviving portions of his two major works—the Annals and the Histories—examine the reigns of the Roman Emperors Tiberius, Claudius, Nero and those who reigned in the Year of the Four Emperors...
  
   Agricola (end of 1st c.)
• Tacitus
  Tacitus
  Publius Cornelius Tacitus was a senator and a historian of the Roman Empire. The surviving portions of his two major works—the Annals and the Histories—examine the reigns of the Roman Emperors Tiberius, Claudius, Nero and those who reigned in the Year of the Four Emperors...
  
   Annales (end of 1st c.)
• Tacitus
  Tacitus
  Publius Cornelius Tacitus was a senator and a historian of the Roman Empire. The surviving portions of his two major works—the Annals and the Histories—examine the reigns of the Roman Emperors Tiberius, Claudius, Nero and those who reigned in the Year of the Four Emperors...
  
   Historiae (end of 1st c.)
• Vegetius
  Vegetius
  Publius Flavius Vegetius Renatus, commonly referred to simply as Vegetius, was a writer of the Later Roman Empire. Nothing is known of his life or station beyond what he tells us in his two surviving works: Epitoma rei militaris , and the lesser-known Digesta Artis Mulomedicinae, a guide to...
  
  De re militari (late 4th c.)

External links

• Roman Military Diplomas Online
• Batavian auxiliaries re-enactors
• List of auxiliary units in Britain
• Vindolanda Tablets Online