The Organization of the Imperial Government

Abstract

Diocletian was the first to realize that it was no longer possible, if ever it had been, to govern the huge tricontinental land mass of the empire by a single central government. At long last the division of government and administration between the members of the tetrarchy, the two Augusti and their two Caesars, brought about the required decentralization without, for the time being, destroying the unity of the commonwealth. He broke the empire into twelve large districts called dioceses, each administered by a vicar (vicarius) who was appointed by the praetorian prefect of each of the tetrarchs. However, this proved inadequate for efficient administration. A new layer, therefore, was introduced by Constantine after he had reached the sole emperorship: He divided the empire further into four geographical areas called prefectures — a measure possibly already introduced by Diocletian —, each under one of the four praetorian prefects as imperial viceroys or representatives of the tetrarchs. The previous subdivision into districts — dioceses —, now raised to 14, was retained. Certainly the new territorial units, though still large, were manageable provided they were further subdivided. This measure, initiated likewise already by Diocletian (296), was undertaken by creating, within each diocese, a number of units called provinces.¹ The term, however, had little in common with the territories previously so named. The former differentiation between imperial and senatorial provinces had disappeared already under the Severi. Egypt, holding out longest, had lost its special status in 296. In order to avoid rebellions against the central power in which the military and the civilian leaders would join forces, administrative circumscriptions of the provinces did no longer correspond to areas of military command. The governors of the new provinces were given the title corrector or praeses.