The Roman Army, 31 BC–AD 337: A Sourcebook

2 The officers
CENTURIONS
Centurions were an important part of the command structure of the
Roman army and held a more responsible position than that of noncommissioned
officers in modern armies. There were 59 centurions in
a legion, with six centuries of 80 men in each of the ten cohorts, except
the first, which consisted of five centuries of double strength. There
were several avenues of promotion to the centurionate: (1) men of
equestrian status were sometimes admitted directly from civilian life.
Doubtless some sought to escape from troubles at home by enlistment,
and the substantial pay rates for centurions might help allay financial
anxieties (about 18,000 sesterces in the second century AD, 72,000 for
a chief centurion). The fact that equestrians were prepared to enlist
demonstrates the status of the centurionate, but also shows that not all
centurions were professional, well-trained soldiers. Men of equestrian
rank, because of their social standing and superior education could
expect rapid promotion; (2) legionaries with long service; serving
legionaries will have made up the largest proportion of new centurions
in any one year; they were generally men who had held a number of
special posts and responsibilities (see pp. 28–32); (3) centurions and
decurions of auxiliary units; (4) urban soldiers, especially praetorians,
who had completed their term of military service in Rome.
Rules of seniority within the centurionate are obscure, and the
reconstruction of elaborate schemes of promotion is not justified on
the basis of the evidence of career inscriptions, which cannot tell us
why and how a man was promoted. The six centurions in each cohort
were pilus prior, pilus posterior, princeps prior, princeps posterior,
hastatus prior, hastatus posterior, and it is possible that centurions in
all cohorts except the first were equal in rank, distinguished only by
seniority. Promotion was then to the first cohort, whose five centurions
were the most senior and were known as the primi ordines; the centurion