The Legion
The Roman Army in Britain
From the time of Augustus (who originated the army structure) until about 270AD there were consistently about 30 legions, each with a nominal strength of over 5,000 men. These were made up of Roman citizens, but not necessarily from Italy
The structure of the theoretical legion was as follows:
The Legate, the commander of the Legion would be a senator probably in his thirties and usually was appointed for 3 years.
- Senior Tribune, normally second in command from a senatorial family, in his twenties with little experience
- Camp Prefect third in command was a former senior centurion
- 5 Tribunes with no specific duties from the equestrian order
- 1 primus pilus, the most senior centurion in the legion, responsible first cohort consisting of 5 centuries under a centurion of 160 men. The century was divided into 10 troops of 8 men, who would share a tent or 2 barrack rooms.
- 9 senior centurions each responsible for a cohort of troops of 6 centuries of 80 men, each commanded by a centurion. The century was divided into 10 troops of 8 men, who would share a tent or 2 barrack rooms.
- 120 mounted cavalry. Their role would have probably been more messengers than cavalry, although they had the necessary training
There were 59 centurions in the legion and most had been promoted from the ranks. Each century had optio, who was second in command to the centurion.
Quite often the legions were split up, sometimes garrisoning two or three locations. On occasions large parts of a legion were seconded to support another legion of on the frontier, these were called vexillations.
In the late 1st century, there was a change in the first cohort of the legion, whereby the number of centuries was reduced from 6 to 5 but doubled in size 160 men increasing cohort to 800 men from 480. The centurion of 1st century was most senior in the legion. The troops of the 1st cohort were the elite force. New recruits would be put in one of the other cohorts. The rank of centurion had many grades probably from lieutenant to lieutenant colonel in a modern army.
In addition, the legion had specialists like medical staff. Not only were the legions heavy infantry but they had building skills to construct roads, forts, bridges, metalworking engineers, artillerymen and quarry, the staff were called Immunes.
Although part of the century structure without guard duties and other site duties they part of the century structure..This applied the Cavalry formation as well.
They were responsible for building Hadrian’s Wall, the roads the bridges and most of the forts.
On the basis described the legion’s theoretical manning was 800 in the 1st cohort and 480 in the other nine, making 5120, plus 120 cavalrymen. There is no certainty, it is best to say the legion had 5000/5500 men.
It is thought that by the 3rd century the 3 legions in Britain were largely British born.
The uniform changed over time, but the represents the legionary uniform at the time the Wall was built. It is a pretty accurate representation thanks to a remarkable find at Corbridge in 1964, where a complete uniform was found buried in a box, which can now be seen in the Corbridge Roman Museum.
The emphasis was on training and they were the most disciplined troops the world had seen. Their training was described as bloodless battles and their battles bloody drills.
The Auxiliaries
The Roman Army had concentrated on the heavy infantry of the legions, but from the very beginning has used ancillaries to fulfill their need for Calvary and light infantry
This was supplied by the non-Roman auxiliaries from inside and outside the empire. Under Augustus these were formed into regular regiments organised similar to the cohort of the legion. Their training was not a rigorous as the legion, but they were better trained than most of their opponents.
There were 6 types of units:
Cavalry (Ala)
The unit in the cavalry was turma (as against century in the infantry) each with 32 men
Ala quingenaria had 16 turma: 512 men
Ala militaris had 24 turma: 768 men
Infantry Cohorts
Cohort quingenaria 6 centuries: 480men
Cohort militaris: 10 centuries:
800men
Mixed Units
Cohort equitata quingenaria: 6 centuries plus 4 Turma: 608 men
Cohort equitata militaris: 10 centuries plus 8 turma: 1056 men.
Most of the Wall garrisons were of this category.
The militaris cohorts were commander by Tribune and the others by a Prefect in the earlier periods..
In addition there were other units of archers, slinger and even boatmen. No legion would have gone on campaign without a large contingent of ancillaries
About the Ancillaries
The commanders of the ancillaries were generally drawn from the Equestrian class and ranked in society after the senatorial class. In some cases, the command was given to princes of tribes from where the cohort had been recruited. In this case, they had generally been trained in Rome and were Roman citizens and possibly appointed to the Equestrian class. Legionary centurions were sometimes appointed. Their appointment was usually for 3 years. The troopers were freemen and after 25 years of service would become Roman citizens, a privilege enjoyed by their children. In the 1st and 2nd centuries, the cohorts were posted away from their homeland. They were recruited from all over the empire, and sometimes from outside the empire As many units were kept at the same fort for at least a hundred years, it is likely they were manned by locally born recruits, especially the children of the troops, as best job available locally. From 212AD all freemen became citizens. This started a process, where the difference between the legions and ancillaries became blurred.
Legionary Fortresses
After most of England had been mainly subdued, the legions settled into 3 permanent locations, York in 71AD, Caerleon 75AD (south east Wales) and Chester in 79AD.
As most legionary fortress have been built on and it is not clear what they looked like. Inchtuthil is the fortress built on the River Tay by Agricola and never really occupied because of the withdrawal from Scotland arising from the transfer of units from Britain.
Legionary headquarters consisted of a number of offices where the records were kept. The Romans kept a very detailed record in respect of every trooper and accounts of all financial matters. There was a shrine were the legion’s eagle was kept and strong room as the legion’s safe. In addition was a large hall across the building.
The Legate and tribunes would have accommodation as befits their rank and similar to their houses at home.
Legionary Fortresses were not castles in so far as they would not use it to defend the legion from a hostile army. If such an army were to appear they would fight in open ground. It was to prevent a limited attack at night and keep the troopers in the fortress when necessary.
