Equites cataphractarii, or simply cataphractarii for short, were the heavily-armoured cavalry of the 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...

.

Modelled on the cataphracts of 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....

, they were covered from neck-to-toe by lamellar (scale) armour (lorica squamata

Lorica squamata

The Lorica squamata is a type of scale armour used by the ancient Roman military during the Roman Republic and at later periods. It was made from small metal scales sewn to a fabric backing. It is typically seen on depictions of standard bearers, musicians, centurions, cavalry troops, and even...

), and normally armed with a contus, a long lance held in both hands, although sometimes they carried bows instead. In addition, they were armed with swords. In some cases, their horses were covered in scale armour also. Cataphract cavalry was developed by the Roman army to counter Parthian formations of this kind on the eastern frontier and Sarmatian cataphracts 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....

.

It was apparently from the time of the emperor 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...

 (ruled AD 97-117) that the first regular formations of Roman cataphractarii appear in the record. These were all in the auxiliary

Auxiliaries (Roman military)

Auxiliaries formed the standing non-citizen corps of the Roman army of the Principate , alongside the citizen legions...

, not the 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"...

ary corps. The Romans also used the terms contarii (from contus) 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...

for their heavily-armoured cavalry. It is uncertain whether these terms were used interchangeably or whether they implied differences of equipment and role.

The earliest known units of equites cataphractarii, both recorded in the early 2nd century, are the auxiliary cavalry regiments, Ala I Gallorum et Pannoniorum cataphractaria, stationed in Moesia Inferior and the Ala I Ulpia contariorum, stationed in neighbouring Pannonia Inferior. The deployment of these on 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....

 front, rather than in the East, implies that initially the cataphractarii were aimed at countering the Sarmatian, rather than the Parthian threat.

Cataphractarii regiments apparently remained few in number in the army 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...

 (to AD 284). They became more numerous in 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...

, especially in the East. 19 units are recorded in 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...

, of which one was an elite schola regiment of imperial horse guards. All but two of the rest belonged to the comitatus (field armies), with a minority rated 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...

troops. There was just one regiment of cataphract archers.

CATAPHRACTARII REGIMENTS IN THE LATE ROMAN ARMY

Corps	Normal HQ	Name of regiment (* = 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... grade)	No. of regiments	No. of effectives**
	Byzantium Byzantium Byzantium was an ancient Greek city, founded by Greek colonists from Megara in 667 BC and named after their king Byzas . The name Byzantium is a Latinization of the original name Byzantion...	Schola scutariorum clibanariorum*	1	500
COMITATUS PRAESENTALIS I	Nicaea	Comites clibanarii* Equites cataphractarii Biturigenses Equites I clibanarii Parthi	3	1,500
COMITATUS PRAESENTALIS II	Adrianopolis Adrianópolis Adrianópolis is a town and municipality in the state of Paraná in the Southern Region of Brazil.-References:...	Equites Persae clibanarii* Equites cataphractarii Equites cataphractarii Ambianenses Equites II clibanarii Parthi	4	2,000
COMITATUS ORIENTIS	Antioch Antioch Antioch on the Orontes was an ancient city on the eastern side of the Orontes River. It is near the modern city of Antakya, Turkey.Founded near the end of the 4th century BC by Seleucus I Nicator, one of Alexander the Great's generals, Antioch eventually rivaled Alexandria as the chief city of the...	Comites cataphractarii Bucellarii iuniores Equites promoti clibanarii Equites IV clibanarii Parthi Cuneus equitum II clibanariorum Palmirenorum	4	1,750
COMITATUS THRACIAE	Marcianopolis Marcianopolis Marcianopolis or Marcianople was an ancient Roman city in Thracia. It was located at the site of modern day Devnya, Bulgaria.-History:...	Equites cataphractarii Albigenses	1	500
LIMES THEBAIDOS	Thebes (Egypt)	Ala I Iovia cataphractaria	1	250
LIMES SCYTHAE		Cuneus equitum cataphractariorum	1	250
TOTAL EAST			15	6,750
COMITATUS PRAESENTALIS	Milan Milan Milan is the second-largest city in Italy and the capital city of the region of Lombardy and of the province of Milan. The city proper has a population of about 1.3 million, while its urban area, roughly coinciding with its administrative province and the bordering Province of Monza and Brianza ,...	Comites Alani* Equites sagitarii clibanarii	2	1,000
COMITATUS AFRICAE	Carthage Carthage Carthage , implying it was a 'new Tyre') is a major urban centre that has existed for nearly 3,000 years on the Gulf of Tunis, developing from a Phoenician colony of the 1st millennium BC...	Equites clibanarii	1	500
COMITATUS BRITANNIARUM	London London London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...	Equites cataphractarii iuniores	1	500
TOTAL WEST			4	2,000

** Assuming 500 effectives in comitatus units, 250 for 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...