at the age of twenty-five, to
become a candidate for the quaestorship, which gave admission to the
Senate. From the quaestorship the official career of the senator led
through the regular magistracies, the aedileship or tribunate, and the
praetorship, to the consulship. As an ex-praetor and ex-consul a senator
might be appointed a promagistrate to govern a senatorial province; a
legate to command a legion or administer an imperial province; or a
curator in charge of some administrative commission in Rome or Italy.

During the republic the Senate had been the actual center of the
administration and Augustus intended that it should continue to be so for
the greater part of the empire. Through the ordinary magistrates it should
govern Rome and Italy, and through the promagistrates the senatorial
provinces. Furthermore, the state treasury, the _aerarium saturni_,
supported by the revenues from Italy and the Senate's provinces, remained
under the authority of that body. However, to render it capable of
fulfilling its task and to reestablish its prestige, the Senate which now
numbered over one thousand had to be purged of many undesirable members
who had been admitted to its roll during the recent civil wars. Therefore,
in 28 B. C., Augustus in his consular capacity supervised a revision of
the senatorial list whereby two hundred unworthy persons were excluded. On
that occasion his name was placed at the head of the new roll as the
_princeps senatus_. A second recension ten years later reduced the total
membership to six hundred. A third, in 4 A. D., commenced through a
specially chosen committee of three with the object of further reducing
their number was not carried out. The Senate was automatically recruited
by the annual admission of the twenty quaestors, but in addition the
princeps enjoyed the right of appointing new members who might be entered
upon the roll of the Senate among the past holders of any magistracy. In
this way many prominent equestrians were admitted to the senatorial order.

*The equestrian order.* For the conduct of his share of the public
administration the princeps required a great number of assistants in his
personal employ. For his legates to command the legions or his provinces
with delegated military authority Augustus could draw upon the senators,
but both custom and the prestige of the Senate forbade their entering his
service in other capacities. On the other hand, freedmen and slaves, who
m