Roman centuriation
Encyclopedia
Centuriation was a field system
used by the Romans
for land division. It developed from the system used earlier for laying out castra
(fortresses) and in the founding of new cities.
Centuriation is characterised by the regular layout, on a square grid
traced using surveyor's
instruments, of roads, canals and agricultural plots for allocation to settlers (in many cases Roman army
veterans) in each new colony
.
Its study is very important for reconstructing landscape history
in many former areas of the Roman empire
.
). The development of the geometric and operational characteristics that were to become standard came with the founding of the Roman colonies in the Po valley
, starting with Ariminum (Rimini
) in 268 BCE.
The agrarian law introduced by Tiberius Gracchus
in 133 BCE, which included the privatisation of the ager publicus
, gave a great impetus to land division through centuriation.
Centuriation was used later for land reclamation
and the foundation of new colonies as well as for the allocation of land to veterans of the many civil wars of the late Republic and early Empire, including the battle of Philippi
in 42 BCE. This is mentioned by Virgil
, in his Eclogues, when he complains explicitly about the allocation of his lands near Mantua
to the soldiers who had participated in that battle.
Centuriation was widely used throughout Italy
and also in some provinces. For example, careful analysis has identified, in the area between Rome
and Salerno
, 80 different centuriation systems created at different times.
The surveyor first identified a central viewpoint, the umbilicus agri or umbilicus soli. He then took up his position there and, looking towards the west, defined the territory with the following names:
He then traced the grid using an instrument known as a groma
, tracing two road axes perpendicular to each other:
's proposal to create a grid of Townships
for survey purposes, which ultimately led to the United States
Public Land Survey System
. The similarity of the two systems is empirically obvious in certain parts of Italy, for example, where traces of centuriation have remained.
However, Thrower points out that, unlike the later US system, "not all Roman centuriation displays consistent orientation".
This is because, for practical reasons, the orientation of the axes did not always coincide with the four cardinal points and followed instead the orographic features of the area, also taking into account the slope of the land and the flow of rainwater along the drainage channels that were traced (centuriation of Florentia
(Florence
). In other cases, it was based on the orientation of existing lines of communication (centuriation along the Via Emilia) or other geomorphological features.
Centuriation is typical of flat land, but centuriation systems have also been documented in hilly country.
(surveyors).
In such cases, the grid was traced by extending the urban cardo maximus and the decumanus maximus through the gates of the city into the surrounding agricultural land.
Parallel secondary roads (limites quintarii) were then traced on both sides of the initial axes at intervals of 100 actus
(about 3.5 km). The territory was thus divided into square areas.
The road network density was then increased with other roads parallel to those already traced at a distance from each other of 20 actus (710.40 m). Each of the square areas - 20 x 20 actus - resulting from this further division was called a centuria
or century.
This dimension of the centuria became prevalent in the period when the large areas of the Po Valley were delimited, while smaller centuries of 10 x 10 actus, as the name centuria suggests, had formerly been used.
The land was divided after the completion of the roads.
Each century was divided into 10 strips, lying parallel to the cardo and the decumanus, with a distance between them of 2 actus (71.04 m), thus forming 100 squares (heredia) of about 0.5 hectares each: 100 heredia = 1 centuria.
Each heredium
was divided in half along the north-south axis thus creating two jugera: one jugerum
, from jugum (yoke), measured 2523 square metres, which was the amount of land that could be ploughed in one day by a pair of oxen.
Traces of centuriation in the Roman Province of Gallia Narbonensis
Traces of centuriation in the Roman Province of Hispania Tarraconensis
Field system
The study of field systems in landscape history is concerned with the size, shape and orientation of a number of fields. These are often adjacent, but may be separated by a later feature.-Types of field system:...
used by the Romans
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
for land division. It developed from the system used earlier for laying out castra
Castra
The Latin word castra, with its singular castrum, was used by the ancient Romans to mean buildings or plots of land reserved to or constructed for use as a military defensive position. The word appears in both Oscan and Umbrian as well as in Latin. It may have descended from Indo-European to Italic...
(fortresses) and in the founding of new cities.
Centuriation is characterised by the regular layout, on a square grid
Grid plan
The grid plan, grid street plan or gridiron plan is a type of city plan in which streets run at right angles to each other, forming a grid...
traced using surveyor's
Surveying
See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...
instruments, of roads, canals and agricultural plots for allocation to settlers (in many cases 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...
veterans) in each new colony
Colonia (Roman)
A Roman colonia was originally a Roman outpost established in conquered territory to secure it. Eventually, however, the term came to denote the highest status of Roman city.-History:...
.
Its study is very important for reconstructing landscape history
Landscape history
Landscape history is the study of the way in which humanity has changed the physical appearance of the environment - both present and past. It is sometimes referred to as landscape archaeology...
in many former areas 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....
.
History
The Romans began to use centuriation for the foundation, in the fourth century BCE, of new colonies in the ager Sabinus (for example, TerracinaTerracina
Terracina is a town and comune of the province of Latina - , Italy, 76 km SE of Rome by rail .-Ancient times:...
). The development of the geometric and operational characteristics that were to become standard came with the founding of the Roman colonies in the Po valley
Po Valley
The Po Valley, Po Plain, Plain of the Po, or Padan Plain is a major geographical feature of Italy. It extends approximately in an east-west direction, with an area of 46,000 km² including its Venetic extension not actually related to the Po River basin; it runs from the Western Alps to the...
, starting with Ariminum (Rimini
Rimini
Rimini is a medium-sized city of 142,579 inhabitants in the Emilia-Romagna region of Italy, and capital city of the Province of Rimini. It is located on the Adriatic Sea, on the coast between the rivers Marecchia and Ausa...
) in 268 BCE.
The agrarian law introduced by Tiberius Gracchus
Tiberius Gracchus
Tiberius Sempronius Gracchus was a Roman Populares politician of the 2nd century BC and brother of Gaius Gracchus. As a plebeian tribune, his reforms of agrarian legislation caused political turmoil in the Republic. These reforms threatened the holdings of rich landowners in Italy...
in 133 BCE, which included the privatisation of the ager publicus
Ager publicus
The ager publicus is the Latin name for the public land of Ancient Rome. It was usually acquired by expropriation from Rome's enemies.In the earliest periods of Roman expansion in central Italy, the ager publicus was used for Roman and Latin colonies...
, gave a great impetus to land division through centuriation.
Centuriation was used later for land reclamation
Land reclamation
Land reclamation, usually known as reclamation, is the process to create new land from sea or riverbeds. The land reclaimed is known as reclamation ground or landfill.- Habitation :...
and the foundation of new colonies as well as for the allocation of land to veterans of the many civil wars of the late Republic and early Empire, including the battle of Philippi
Battle of Philippi
The Battle of Philippi was the final battle in the Wars of the Second Triumvirate between the forces of Mark Antony and Octavian and the forces of Julius Caesar's assassins Marcus Junius Brutus and Gaius Cassius Longinus in 42 BC, at Philippi in Macedonia...
in 42 BCE. This is mentioned by Virgil
Virgil
Publius Vergilius Maro, usually called Virgil or Vergil in English , was an ancient Roman poet of the Augustan period. He is known for three major works of Latin literature, the Eclogues , the Georgics, and the epic Aeneid...
, in his Eclogues, when he complains explicitly about the allocation of his lands near Mantua
Mantua
Mantua is a city and comune in Lombardy, Italy and capital of the province of the same name. Mantua's historic power and influence under the Gonzaga family, made it one of the main artistic, cultural and notably musical hubs of Northern Italy and the country as a whole...
to the soldiers who had participated in that battle.
Centuriation was widely used throughout Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
and also in some provinces. For example, careful analysis has identified, in the area between Rome
Rome
Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...
and Salerno
Salerno
Salerno is a city and comune in Campania and is the capital of the province of the same name. It is located on the Gulf of Salerno on the Tyrrhenian Sea....
, 80 different centuriation systems created at different times.
System and Procedure
Various land division systems were used, but the most common was known as the ager centuriatus system.The surveyor first identified a central viewpoint, the umbilicus agri or umbilicus soli. He then took up his position there and, looking towards the west, defined the territory with the following names:
- ultra, the land he saw in front of him;
- citra, the land behind him;
- dextera, the land to his right;
- sinistra, the land to his left.
He then traced the grid using an instrument known as a groma
Groma surveying
The Groma or gruma was the principal Roman surveying instrument. It comprised a vertical staff with horizontal cross pieces mounted at right-angles on a bracket. Each cross piece had a plumb line hanging vertically at each end...
, tracing two road axes perpendicular to each other:
- the first, generally oriented east-west, was called decumanus maximusDecumanus MaximusIn Roman city planning, a decumanus was an east-west-oriented road in a Roman city, castra , or colonia. The main decumanus was the Decumanus Maximus, which normally connected the Porta Praetoria to the Porta Decumana .This name comes from the fact that the via decumana or decimana In Roman city...
, which was traced taking as reference the place where the sun rose in order to know exactly where east was; - the second, with a north-south orientation, was called cardo maximus.
Measurement Instruments
- GromaGroma surveyingThe Groma or gruma was the principal Roman surveying instrument. It comprised a vertical staff with horizontal cross pieces mounted at right-angles on a bracket. Each cross piece had a plumb line hanging vertically at each end...
- ChorobatesChorobatesA chorobates was a kind of level used in classical antiquity. It was composed of a wooden frame, made in the form of a beam which was fitted with a water level, and two supports at the end of the beam. It is described by Vitruvius . It is believed to be the instrument that was used to level the...
for levels - DioptraDioptraA dioptra is a classical astronomical and surveying instrument, dating from the 3rd century BCE. The dioptra was a sighting tube or, alternatively, a rod with a sight at both ends, attached to a stand...
for levels and angles of slopes
Orientation
It has been suggested that the Roman centuriation system inspired Thomas JeffersonThomas Jefferson
Thomas Jefferson was the principal author of the United States Declaration of Independence and the Statute of Virginia for Religious Freedom , the third President of the United States and founder of the University of Virginia...
's proposal to create a grid of Townships
Survey township
Survey township, sometimes called Congressional township, as used by the United States Public Land Survey System, refers to a square unit of land, that is nominally six miles on a side...
for survey purposes, which ultimately led to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
Public Land Survey System
Public Land Survey System
The Public Land Survey System is a method used in the United States to survey and identify land parcels, particularly for titles and deeds of rural, wild or undeveloped land. Its basic units of area are the township and section. It is sometimes referred to as the rectangular survey system,...
. The similarity of the two systems is empirically obvious in certain parts of Italy, for example, where traces of centuriation have remained.
However, Thrower points out that, unlike the later US system, "not all Roman centuriation displays consistent orientation".
This is because, for practical reasons, the orientation of the axes did not always coincide with the four cardinal points and followed instead the orographic features of the area, also taking into account the slope of the land and the flow of rainwater along the drainage channels that were traced (centuriation of Florentia
Florentia
Florentia is a commune in the Jura department in Franche-Comté in eastern France.- References :*...
(Florence
Florence
Florence is the capital city of the Italian region of Tuscany and of the province of Florence. It is the most populous city in Tuscany, with approximately 370,000 inhabitants, expanding to over 1.5 million in the metropolitan area....
). In other cases, it was based on the orientation of existing lines of communication (centuriation along the Via Emilia) or other geomorphological features.
Centuriation is typical of flat land, but centuriation systems have also been documented in hilly country.
Centuriation of the surrounding territory
Sometimes the umbilicus agri was located in a city or a castrum. This central point was generally referred to as groma, from the name of the instrument used by the gromaticiGromatici
Gromatici , or agrimensores, was the name for land-surveyors amongst the ancient Romans...
(surveyors).
In such cases, the grid was traced by extending the urban cardo maximus and the decumanus maximus through the gates of the city into the surrounding agricultural land.
Parallel secondary roads (limites quintarii) were then traced on both sides of the initial axes at intervals of 100 actus
Ancient Roman units of measurement
The ancient Roman units of measurement were built on the Hellenic system with Egyptian, Hebrew, and Mesopotamian influences. The Roman units were comparatively consistent and well documented.-Length:Notes...
(about 3.5 km). The territory was thus divided into square areas.
The road network density was then increased with other roads parallel to those already traced at a distance from each other of 20 actus (710.40 m). Each of the square areas - 20 x 20 actus - resulting from this further division was called a centuria
Ancient Roman units of measurement
The ancient Roman units of measurement were built on the Hellenic system with Egyptian, Hebrew, and Mesopotamian influences. The Roman units were comparatively consistent and well documented.-Length:Notes...
or century.
This dimension of the centuria became prevalent in the period when the large areas of the Po Valley were delimited, while smaller centuries of 10 x 10 actus, as the name centuria suggests, had formerly been used.
| Width | Equivalent | Name |
|---|---|---|
| 40 Roman feet | 11.84 m | decumanus maximus |
| 20 Roman feet | 5.92 m | cardo maximus |
| 12 Roman feet | 3.55 m | limites quintarii |
| 8 Roman feet | 2.37 m | Other roads |
The land was divided after the completion of the roads.
Each century was divided into 10 strips, lying parallel to the cardo and the decumanus, with a distance between them of 2 actus (71.04 m), thus forming 100 squares (heredia) of about 0.5 hectares each: 100 heredia = 1 centuria.
Each heredium
Ancient Roman units of measurement
The ancient Roman units of measurement were built on the Hellenic system with Egyptian, Hebrew, and Mesopotamian influences. The Roman units were comparatively consistent and well documented.-Length:Notes...
was divided in half along the north-south axis thus creating two jugera: one jugerum
Jugerum
', jugera or ' was a Roman unit of measurement of area, 240 ft or 73 m in length and 120 ft or 37 m in breadth, containing therefore 28,800 square feet...
, from jugum (yoke), measured 2523 square metres, which was the amount of land that could be ploughed in one day by a pair of oxen.
Regions where centuriation was used
Even today, in some parts of Italy, the landscape of the plain is determined by the outcome of Roman centuriation, with the persistence of straight elements (roads, drainage canals, property divisions) which have survived territorial development and are often basic elements of urbanisation, at least until the twentieth century, when the human pressure of urban growth and infrastructures destroyed many of the traces scattered throughout the agricultural countryside.Significant examples of centuriation in Italy
- CesenaCesenaCesena is a city and comune in the Emilia-Romagna region of northern Italy, south of Ravenna and west of Rimini, on the Savio River, co-chief of the Province of Forlì-Cesena. It is at the foot of the Apennines, and about 15 km from the Adriatic Sea.-History:Cesena was originally an Umbrian...
, and in particular the country to the north-east and north-west of the city; - Central RomagnaRomagnaRomagna is an Italian historical region that approximately corresponds to the south-eastern portion of present-day Emilia-Romagna. Traditionally, it is limited by the Apennines to the south-west, the Adriatic to the east, and the rivers Reno and Sillaro to the north and west...
; - PaduaPaduaPadua is a city and comune in the Veneto, northern Italy. It is the capital of the province of Padua and the economic and communications hub of the area. Padua's population is 212,500 . The city is sometimes included, with Venice and Treviso, in the Padua-Treviso-Venice Metropolitan Area, having...
, eastern area of the province; in this area of VenetiaVenetiaVenetia is a name used mostly in a historical context for the area of Northeast Italy, corresponding approximately to the present-day Italian administrative regions of the Veneto and Friuli-Venezia Giulia...
, the geometrical layout of the landscape is known as the Graticolato Romano; - Ager Campanus (Acerra, Capua, Nola, Atella);
- FlorenceFlorenceFlorence is the capital city of the Italian region of Tuscany and of the province of Florence. It is the most populous city in Tuscany, with approximately 370,000 inhabitants, expanding to over 1.5 million in the metropolitan area....
(FlorentiaFlorentiaFlorentia is a commune in the Jura department in Franche-Comté in eastern France.- References :*...
), first century CE, in the plain to the west to PratoPratoPrato is a city and comune in Tuscany, Italy, the capital of the Province of Prato. The city is situated at the foot of Monte Retaia , the last peak in the Calvana chain. The lowest altitude in the comune is 32 m, near the Cascine di Tavola, and the highest is the peak of Monte Cantagrillo...
and beyond. - Province of BergamoProvince of BergamoThe Province of Bergamo is a province in the Lombardy region of Italy. It has a population of 1,098,740 , an area of 2,722.86 square km, and contains 244 comuni...
: There are still several easily identifiable traces, from the low plain almost to the foot of the hills, for example, the straight road of about ten kilometresKilometreThe kilometre is a unit of length in the metric system, equal to one thousand metres and is therefore exactly equal to the distance travelled by light in free space in of a second...
between SpiranoSpiranoSpirano is a comune in the Province of Bergamo in the Italian region of Lombardy, located about 40 km northeast of Milan and about 13 km south of Bergamo...
and StezzanoStezzanoStezzano is a comune in the Province of Bergamo in the Italian region of Lombardy, located about 40 km northeast of Milan and about 8 km south of Bergamo.-Main sights:*Villa Moroni *Villa Caroli-Zanchi...
, through Comun NuovoComun NuovoComun Nuovo is a comune in the Province of Bergamo in the Italian region of Lombardy, located about 40 km northeast of Milan and about 9 km south of Bergamo...
; there are also traces of agricultural centuriation identifiable in the street network of TreviglioTreviglioTreviglio is a town and comune in the province of Bergamo, in Lombardy, northern Italy. It lies 20 km south of the capital city, in the lower territory called "Bassa" marked by the Adda and the Serio rivers....
.
Traces of centuriation in the Roman Province of Gallia NarbonensisGallia NarbonensisGallia Narbonensis was a Roman province located in what is now Languedoc and Provence, in southern France. It was also known as Gallia Transalpina , which was originally a designation for that part of Gaul lying across the Alps from Italia and it contained a western region known as Septimania...
(southern France)
- Béziers
- Valence
- Orange (Orange B)
Traces of centuriation in the Roman Province of Hispania TarraconensisHispania TarraconensisHispania Tarraconensis was one of three Roman provinces in Hispania. It encompassed much of the Mediterranean coast of Spain along with the central plateau. Southern Spain, the region now called Andalusia, was the province of Hispania Baetica...
(present-day Catalonia)
- Tarragona
- Empúries
- Girona
- Barcelona
- Cerdanya
- Isona (Pallars Jussà)
- Guissona
- Lleida
- els Prats de Rei (antiga Segarra romana)
- la Seu d'Urgell o Castellciutat (probable)
- Bages (probable)
- Castell-rosselló (probable)
See also
- Ancient Roman units of measurementAncient Roman units of measurementThe ancient Roman units of measurement were built on the Hellenic system with Egyptian, Hebrew, and Mesopotamian influences. The Roman units were comparatively consistent and well documented.-Length:Notes...
- Ancient Roman architecture,
- Roman roads
- Drainage and centuriation in the Po ValleyPo ValleyThe Po Valley, Po Plain, Plain of the Po, or Padan Plain is a major geographical feature of Italy. It extends approximately in an east-west direction, with an area of 46,000 km² including its Venetic extension not actually related to the Po River basin; it runs from the Western Alps to the...
and Po delta - Ager RomanusAger RomanusGeographically, the Ager Romanus is the name given to the immense rural area around the city of Rome. Politically and historically, it has represented the area of influence of Rome's municipal government...
- Aerial archaeologyAerial archaeologyAerial archaeology is the study of archaeological remains by examining them from altitude.The advantages of gaining a good aerial view of the ground had been long appreciated by archaeologists as a high viewpoint permits a better appreciation of fine details and their relationships within the wider...