The Imperial Roman Army
As Rome moved from Republic to Empire after Augustus all but became Emperor after the Battle of Actium in 31 BC, its army became larger and more powerful. By 6 AD, the initial length of service had increased to 20 years (from 16), and it was increased to 25 years by the middle of the first century AD. Rome was in a very pronounced spell of expansion by now, and since soldiers were usually fighting hundreds or even thousands of miles from home, they usually served for far longer than their minimum requirement. It wasn’t unusual for long-term soldiers to mutiny.
By the time of Augustus’ death in 14 AD, the Roman imperial army consisted of 250,000 men split between 25 legions and 250 units of auxiliaries. The peak number of soldiers was 450,000 in 211 AD which consisted of 33 legions and 400 auxiliary units. When Augustus was emperor, the imperial army contained:
- Legions: Formations comprised of 5,000 heavy infantry units. You had to be a Roman citizen to be eligible.
- Auxilia: These regiments consisted of 500 men per unit and were recruited from non-citizens of the empire. The Auxilia provided the imperial army with the vast majority of its cavalry, archers, light infantry and other specialists.
- Numeri: Allied native or ‘barbarian’ units recruited from outside the Empire who basically operated as mercenaries. They were led by their own people and used their own armor and weapons.
Why Join the Army?
The Marian reforms led to a dramatic increase in the army’s size. Recruits knew that the job involved lots of traveling with a high risk of death, so why join? Bear in mind that a large proportion of recruits would have been 18-20 years of age by the 1st century BC. It took a long time to complete your service and while the pay was reasonable, it wasn’t an enormous amount plus deductions were made for food and clothing.
Add in the harsh conditions one would face and the strict disciplinary procedures, and you have to question the motives of those who joined. In reality, however, it was a no-brainer for those who came from poor backgrounds. The army provided a steady source of income, food, and doctors. Then there was the small matter of ‘supplementing’ their income with plunder plus the chance of honor and glory.
Although the initial pay wasn’t terrific, it got significantly better as you climbed the military ladder. For example, a centurion (leader of a unit of approximately 80 men) received on average, 18 times more than the average soldier at 13,000 denarii by the 1st century AD. A first cohort centurion received 27,000 denarii while a primi ordines (senior centurion) received 54,000 denarii.
Outside of battle, soldiers would participate in route marches up to three times a month and they would also practice maneuvers in the field. Soldiers also had to help build roads and bridges, man hospitals, bake bread and fetch fuel. Every aspect of a Roman soldier’s training was geared towards one thing, however; battle.