38 THE ROMAN EMPIRE
empire (as in the Alps, central Sardinia or Judaea). The replacement from
the reign of Claudius of prefect by procurator, a civilian title, was designed
to refl ect the success (sometimes as in Judaea more apparent than real) of
the pacifi cation process in the areas concerned. Secondly, emperors appointed
equestrians (and sometimes freedmen) with the title of procurator of
Augustus as their fi nancial agents, with the task of superintending the
imperial properties. Thirdly, procurators appear in the provinces as tax
offi cials, collecting customs dues, the inheritance tax and other indirect
taxes. The offi cials in these last two categories were potentially infl uential,
and sometimes acted as a counterweight to the senatorial offi cials, but they
cannot be said to have increased the administrative burden on the cities.
Finally, the military function of the equestrian order should be stressed.
There were around 360 posts annually available for senior offi cers of
equestrian rank: prefectures of cohorts, military tribunates and prefectures
of alae (cavalry units). Progression through this series of posts, which were
already being termed the equestrian militiae by the reign of Augustus’
successor Tiberius (Velleius Paterculus 2.111), was a necessary precursor to
the tenure of posts in the civil administration. The careers (and, because of
mortality patterns, the lives) of many equestrians proceeded no further.
Military service must be seen as the basis of the equestrian career.^8
Developments in Rome and in the imperial court affected both equestrian
and senatorial careers. The emperors gave the city of Rome for the fi rst time
a continuous administration. By the end of the reign of Augustus there
existed a ‘police’ force, a fi re department and an offi ce for the grain supply.
These prefectures fell to a senior senator and two equestrians ( praefectus
vigilum, praefectus annonae ). Another leading equestrian was appointed
praetorian prefect, commander of the emperor’s elite bodyguard, the
praetorian guard. Because of his proximity to the emperor and control of
troops in the vicinity of the capital, the praetorian prefect’s power was
considerable: to hinder its abuse two prefects were usually appointed.^9
The structure of the central fi nancial administration has been the subject
of debate, much of it stemming from the various possible meanings of the
word fi scus. The main treasury, the aerarium , into which provincial taxes
fl owed, was headed by a pair of prefects who were chosen by the emperor
from the ranks of former praetors. Similar offi cials were appointed over the
military treasury ( aerarium militare ) created by Augustus to provide benefi ts
for veterans on retirement. Much of the fi scal responsibility, however, lay
not with these men, but with the emperor’s freedmen and then from the
middle of the fi rst century with a high- ranking equestrian procurator
( a rationibus ), who with a staff of imperial freedmen and slaves kept
accounts of the empire’s revenues and expenditures.^10 It does not follow
from the fact that these accounts were kept by the emperor’s slaves and
freedmen that there was no division between public fi nances and those of
the imperial household.^11 But in the end the distinction between the two
may not have been of great practical importance, because the emperor