upport
of the power of the princeps; it was also the mainstay of the _pax Romana_
which endured with two brief interruptions from the battle of Actium to
the death of Severus Alexander and was the necessary condition for the
civilizing mission of Rome.

IV. THE PROVINCES UNDER THE PRINCIPATE

It is to the provinces that one must turn to win a true appreciation of
the beneficial aspects of Roman government during the principate. As
Mommsen(16) has said: "It is in the agricultural towns of Africa, in the
homes of the vine-dressers on the Moselle, in the flourishing townships of
the Lycian mountains, and on the margin of the Syrian desert that the work
of the imperial period is to be sought and found." In this sphere the
chief tasks of the principate were the correction of the abuses of the
republican administration and the extension of Graeco-Roman civilization
over the barbarian provinces of the west and north. How well this latter
work was done is attested not merely by the material remains of once
flourishing communities but also by the extent to which the civilization
of Western Europe rests upon the basis of Roman culture.

*Number of the provinces.* At the establishment of the principate there
were about thirteen provinces, at the death of Augustus twenty-eight, and
under Hadrian forty-five. In the course of the third century the latter
number was considerably increased. The new provinces were formed partly by
the organization of newly conquered countries as separate administrative
districts and partly by the subdivision of larger units. At times this
subdivision was made in order to relieve a governor of an excessively
heavy task and to improve the administration, and at times it proceeded
from a desire to lessen the dangers of a revolt of the army by breaking up
the larger military commands.

*Senatorial and imperial provinces.* As we have seen the provinces were
divided into two classes, senatorial or public and imperial or Caesarian,
corresponding to the division of administrative authority between the
Senate and the princeps. The general principle laid down by Augustus that
the garrisoned provinces should come under the authority of the princeps
was adhered to, and consequently certain provinces were at times taken
over by the latter in view of military necessities while others were given
up by him to the Senate. As a rule newly organized provinces were placed
under imperial governors