es of their own households, that is to say, their freedmen, who,
in another capacity, conducted the management of the private estate of the
princeps. An important change was introduced under Claudius, when his
influential freedmen caused the creation within the imperial household of
a number of secretaryships with definite titles that indicated the sphere
of their duties. The chief of these secretaryships were the _a
rationibus_, the _ab epistulis_, the _a libellis_, the _a __cognitionibus_
and the _a studiis._ The _a rationibus_ acted as a secretary of the
treasury, being in charge of the finances of the empire which were
controlled by the princeps; the _ab epistulis_ was a secretary for
correspondence, who prepared the orders which the princeps issued to his
officials and other persons; the _a libellis_ was a secretary for
petitions, who received all requests addressed to the princeps; the _a
__cognitionibus_ served as a secretary for the imperial inquests,
entrusted with the duty of preparing the information necessary for the
rendering of the imperial decision in the judicial investigations
personally conducted by the princeps (_cognitiones_); and the _a studiis_,
or secretary of the records, had the duty of searching out precedents for
the guidance of the princeps in the conduct of judicial or administrative
business. The establishment of these secretaryships in the imperial
household tended to centralize more completely the imperial administration
and to give it greater uniformity and regularity. At the same time the
influence of the freedmen who occupied these important positions was
responsible for the admission of freedmen to many of the minor
administrative procuratorships. It was under Claudius also that the
preliminary military career of the procurators was more definitely fixed.

*The reforms of Hadrian and Septimius Severus.* Hadrian took the next
decisive step in the development of the central administrative offices
when he transformed the secretaryships of the imperial household into
secretaryships of state by filling them with equestrians of procuratorial
rank in place of imperial freedmen. From this time the latter were
restricted to minor positions in the various departments. Under Hadrian
also there was a marked increase in the number of administrative
procuratorships owing to the final abolition of the system of farming the
revenues and their subsequent direct collection by imperial officials as
well