The lowest position an equestrian might hold was also the highest an ordinary soldier could expect to achieve – centurion. These men commanded centuries in the legions or the auxiliary – in the legions, these usually consisted of 80 men. These were the officers who commanded men on a day to day basis, both in war and in camp.
Some men started their careers as centurions, either because they were wealthy or because they were equestrians who could not find a praefecti role. Others were experienced soldiers, usually having served for 15-20 years, who had proved themselves in a more junior position of authority. For an ordinary but hard-working citizen-soldier, this was the path to wealth, status and even a role in local administration.
The most senior centurions were the primi ordines, centurions in the first cohort of a legion. Centurions might work their way up to this prestigious role through posts in other centuries.
The century was the unit men most identified themselves with, but the cohort of six centuries was the basic battlefield unit of a legion. Someone must have commanded the cohort in battle, and though we don’t know for certain, it is likely that this task fell to the pilus prior, the commander of the senior century in the legion.
As these different roles show, the term centurion covered a range of different ranks in today’s terms, rather than being what we would recognize as a single role.
The optio was a centurion’s second in command, supporting him in organizing and commanding 80 men. This was one of three posts collectively known as the principales.
The second of the principales was the signifier – the standard-bearer. He carried the century’s eagle standard, creating a clear point for men to form up around and follow into battle. This was a prestigious post.
The third of the principales was the tesserarius, the guard commander for the century.