The Roman legion in imperial times consisted
of about 5500 legionaries. The legion itself was divided into
ten cohorts. Cohorts 2 to 10 were each of about
500 legionaries whilst the first cohort was larger with some 800
men. Each cohort had it's own standard-bearer or Signifer
and a horn-blower or Cornicen, who was used to
sound commands to the troops.
Each cohort was in turn divided into six smaller tactical units
called centuries, each of around 80 men. Each century was commanded
by a Centurion (who would be equivalent to an
NCO in modern terminology) who was assisted by an Optio,
the centurion's second in command. The chief Centurion in the
legion was called the Primus Pilus and he would
command the first century of the first cohort.
Commanding the legion as a whole were six tribunes
(drawn from the Equites or wealthy Roman middle-class) who were
semi-professional soldiers and usually joined the army as a step
on their political careers. Five of the tribunes were called Tribuni
angusticlavii and the chief tribune was called the Tribunus laticlavius.
The standard bearer for the legion as a whole was the Aquilifer
or Eagle-bearer. His office was regarded as sacred and he was
seen in a way as the embodiment of the whole legion. The loss
of an eagle was regarded as a most shameful event for the entire
legion. In overall command of the legion was the legate,
usually a trusted senator appointed personally by the emperor
himself.
