In order to achieve the best possible administration of their state, the Romans split up the Empire into smaller administrative regions, the provinces (provinciae).

Homogeneous though the Roman administrative system by and large appears, the Romans did leave local self-administration to the Greekss, the approval of the Roman authorities being required only for "enterprises of great pith and moment". The institutions in force in Greek-speaking regions during the Roman period were intimately bound up with the historical traditions of those places, whether inhabited by Greeks or Hellenized local populations. The Romans may have modified many of these customs, but they very rarely tried to abolish them. The diverse Hellenic institutions, therefore, continued to exist and to provide the cultural basis for the future identity of Byzantium.