ty plebs, accustomed to receive its free distributions of
grain, and to be entertained at costly public spectacles, was a heavy
drain upon the resources of the state, the vigorous third estate in the
Italian municipalities supplied the subaltern officers of the legions.
These were the centurions, who were the mainstay of the discipline and
efficiency of the troops, and from whose ranks many advanced to an
equestrian career.

III. THE MILITARY ESTABLISHMENT

*Reorganization of the army.* Upon his return to Italy in 30 B. C.,
Augustus found himself at the head of an army of about 500,000 men. Of
these he released more than 300,000 from service and settled them in
colonies or in their native municipalities upon lands which it was his
boast to have purchased and not confiscated. This done, he proceeded to
reorganize the military establishment. Accepting the lessons of the civil
wars, he maintained a permanent, professional army, recruited as far as
possible by voluntary enlistment. This army comprised two main categories
of troops, the legionaries and the auxiliaries.

*The legions and auxilia.* The legionaries were recruited from Roman
citizens or from provincials who received Roman citizenship upon their
enlistment. Their units of organization, the legions, comprised nearly
6000 men, of whom 120 were cavalry and the rest infantry. The number of
legions was at first eighteen, but was later raised to twenty-five, giving
a total of about 150,000 men. The auxiliaries, who took the place of the
contingents of Italian allies of earlier days, were recruited from among
the most warlike subject peoples of the empire and their numbers were
approximately equal to the legionaries. They were organized in small
infantry and cavalry corps (cohorts and _alae_), each 480 or 960 strong.
At the expiration of their term of service the auxiliaries were granted
the reward of Roman citizenship.

*The praetorians.* A third category of troops, which, although greatly
inferior in number to the legions and auxiliaries, played an exceptionally
influential role in the history of the principate, was the praetorian
guard. This was the imperial bodyguard which attended Augustus in his
capacity of commander-in-chief of the Roman armies. It owed its influence
to the fact that it was stationed in the vicinity of Rome while the other
troops were stationed in the provinces. Under Augustus the praetorian
guard comprised nine coho