When Octavian's Principate was established, following his victory at Aktion in 31 BC, there began for Macedonia -- as for most of the provinces -- a period of peace, order and prosperity.
When Octavian Augustus and the Senate divided the provinces between them (27 BC), the Roman troops withdrew from Macedonia, which became a 'provincia inermis' (unarmed province) under senatorial control. When Diocletian divided the empire in twelve dioceses in 15 BC, Macedonia regained its former boundaries, and became one of the provinces of the dioces of Moesia ('dioecesis Moesiarium'). From 15 BC to 44 AD it became an imperial province administered by a consular legate.
The constant modifications in the administration were to the detriment of both the Senate's power and the autonomy of the Macedonian cities, and to the benefit of the Emperor and his delegates. Internal turbulence and the barbarian incursions of the 2nd and 3rd centuries AD (Costoboci, Carpi, Goths, Heruls) resulted in economic, social and political decline.