The Centurion was a professional officer in the Roman army. Every Roman legion (nominally 6,000 men) was divided into 60 centuries, each of which was commanded by a centurion. The centuries of a legion were grouped into 10 cohorts with 6 centuries in each cohort. Each of the 6 centurions in a cohort had a different rank or grade. However, except for the first cohort, the difference in rank was not significant. The best centurions were ordinarily put into the first cohort, and within that cohort the highest rank was that of primipilus.
The centurions were normally promoted from the ranks of the common soldiers and were usually responsible for discipline in the army. They were well paid and received a greater share of the spoils than the common soldiers. The post was so lucrative that many centurions were able to enter the equestrian class when they retired. Under the republic centurions did not normally advance to become higher officers, but by the time of Augustus there were military tribunes and prefects who had been promoted from the centurionship.