
It also started admitting large numbers of non-citizen barbarian volunteers.

The Late Roman Army (284 – 476 CE) returned to regular annual conscription of citizens. However, many served up to 30 to 40 years on active duty. In Imperial Rome (30 BCE – 284 CE), the conscription based system was entirely replaced by a standing professional army of mainly volunteers serving standard 20-year terms in addition to 5 year as reservists. The Late Republic Period (88 to 30 BCE) saw an increasing number of recruits being volunteers who signed up for 16-year terms as opposed to the max 6-year terms of conscripts. In the M id- R epublic P eriod (300 BC – 88 BC E ), the Romans maintained the levy system but adopted the manipular organi z ation for their legions, in which it was organized into four lines, starting at the front: the velites, the hastati, the principes and the triarii. Warfare during this time primarily involved small scale plundering raids. The E arly Roman army (500 BC to 300 BC E ) was based on an annual levy. #2 It evolved from a short term levies system to a standing professional army Diagram showing organization of the late Republic legion However, by 4th century CE, the legion was a much smaller unit of about 1,000 to 1,500 men and there were more of them. This was later changed to nine cohorts of standard size, each with six centuries of 80 men with the first cohort being of double strength, five double-strength centuries with 160 men each. Until the middle of 1st century CE, a legion comprised of 10 cohorts. Its soldiers lived in the same tent while on campaign or the same bunk room in barracks. Contubernium was the smallest unit in the Roman legion.

However, later it contained 60 to 80 soldiers distributed among 10 contubernia of 8 soldiers.

A centuria was named so as it originally consisted of a hundred soldiers. A legion was divided into cohorts of around 500 men. The legion evolved from around 3,000 men in the Roman Republic to over 5,200 men in the Roman Empire. The term legion is derived from the Latin word legio, which means draft or levy. The legion was the largest unit in the Roman army. #1 The Roman army was divided into units called legions
