Legions

The numerous legions of the civil wars, which on Octavian’s side alone were numbered into the forties, were reorganized after the victory at Alexandria in 30 BC. To these were added several legions which used to belong to Antony’s army and some depleted legions were joined together making up so-called Legiones Geminae (twin legions). This policy, basically one of appeasement to Antony’s veterans combined with the will to preserve some of Caesar’s legionary heritage, caused the confusing legionary series where several different legions had the same number (e.g. Legio X Fretensis, Legio X Gemina). The 28 remaining legions were dispersed across the (border-) provinces Augustus had assigned to himself as still threatened by internal or external enemies. They were in many cases paired off in so-called ‘Doppellager’, possibly to encourage inter-unit competition. It must be mentioned here that these camps did certainly not have a permanent character of a frontier garrison. Instead the Roman legions exuded a permanent warning to both the recently submitted tribes and kingdoms within the empire, as well as a permanent threat of offensive action to the areas outside the area of direct control. Legions were very mobile and often changed position, for instance between summer and winter camps, as Varus was doing when he was attacked by Arminius in 9 AD. Recruitment for the legions in the Augustan era was still very much focused on the Italian citizenry, and, theoretically at least, based on voluntary enlistment. Emergency situations, on the other hand, as after the Pannonian revolt in 6 AD could be a cause for a dilectus, forced recruitment, to keep the armies up to strength. Not every crisis with great losses brought a dilectus with it, however. For instance, the Varian disaster of 9 AD did not lead to a forced attempt to bring the number of legions back up to strength. Structurally the Augustan legion was very much a creature of tradition. It had evolved from the Polybian legion, but was in many ways still the same. The maniple as the basic tactical unit had been replaced by the cohort, but it was still used to identify every centuria in the legion and determined its position in the line of battle. They, the centuriae, were the administrative building blocks of every infantry unit, be they legionary or auxiliary. Made up of ten eight-men contuberniae, the centuria had a paper-strength of eighty men each. The formal internal hierarchy of a centuria was in this period simple and clear: the centurion was assisted by an optio, his second-in-command who hoped to one day gain the centurionate for himself. There were otherwise no other formal positions among the rankers, apart from the distinction between the munifices and immunes. The latter performed one of the honorary duties or specialized tasks that had to be done. Many of those were later formalized and included in the formal hierarchy. The relative position of the sixty centurions of the legion is much discussed. Some would have it that the lowest rank was the centurion of the sixth century of the tenth cohort – the decimus hastatus posterior, evincing the manipular structure - rising steadily over 59 steps up to the centurion of the first century of the first cohort, the so-called primus pilus prior. While the latter’s position as the legion’s senior centurion is undisputed, it is usually thought that all centurions were equal, and only the centurions of the first cohort were more equal than others. In between those two variants, is one which assigns battlefield command – and thus a higher rank – of individual cohorts to the pilus prior of each cohort. As there is no other known commander of that tactical unit, and there are simply not enough tribunes to fulfill this role, this seems a likely solution. Supreme command devolved to the legate, a trusted senator, assisted by a young member of a senatorial family, a tribunus militum laticlavius and five somewhat older equestrian tribunes, tribuni militum angusticlavii. They seem to have functioned as a sort of general staff, messengers and sometimes fulfilled command functions on the battlefield. All of these officers served only year, with the exception of the legate, who sometimes served for a few years more. Because of their relative short terms of service, it is easy to see how the career centurions of the legion gained an important role as the legions collected body of knowledge and advisors to the staff and its commander. Finally, making up the rest of the legion, were the servants of the train, mostly slaves, and a small unit of cavalry. These, some 120 soldiers, were divided in four squadrons, turmae, and served as couriers and scouts when the legion was on the march. They remained on the books of their original century however.