The Roman Army: Leadership and Organization
At any one time the army consisted of 28 to 60 Legions, each containing 4000 to 6000 soldiers, who initially had to be Roman citizens. The Emperor, the supreme commander, appointed his own generals to command the legions in his stead. Each legion had 60 Centurion officers. Auxiliary troops in smaller units consisted of non-Roman cavalry, infantry, archers, and slingers. Combinations of legionary and auxiliary troops gave the army flexibility on varied terrains and against enemies trained in a range of local fighting styles.
Military Pay
During the reign of the emperor Domitian the yearly pay for the military was:
5000 denarii for a centurion
720 denarii for a praetorian
300 denarii for a legionary