To avert a resurgence of the Macedonian kingdom's power, the Romans divided it into four 'merides' (portions). Each of these semi-autonomous areas had an administrative center (Amphipolis, Pella, Thessalonike, and Pelagonia), where levies were taken in and the citizens assembled to elect their local leaders.
The conversion of the country into a Roman province in 148 BC was a formality, which did not result in broad political changes other than the presence of the Roman governor and his legions. The regular levies were not particularly heavy. The powers of the governor -- who was the administrative, military and judicial potentate -- were vast at the period of the Republic. Except for the period from 15 BC to 44 AD, the province was governed by senatorial administrators. Nevertheless, interventions by both the emperor and his legates constantly intensified.
The incorporation of Macedonia into the Roman administration was aided by the existence of cities and autonomous 'koina' (commonalties) of various peoples. The Roman colonies (Dion, Pella , Philippi, Kassandreia) were exempt from direct taxation. The Greek cities had their own laws and leaders, although most were taxed. Some however, such as Thessalonike, Amphipolis and Skotoussa, enjoyed the privileges of a free city ('civitates liberae').
Macedonian cities and ethnic groups conserved a common organisation existing since the Hellenistic period, the Macedonian 'koinon', which was a confederation of the Macedonian communities and was based at Beroia. The Macedonian 'koinon', which was favoured by the Romans, was centred on the Imperial cult, organised games, minted coinage, and could appeal directly to the emperor for solutions to matters pertaining to pan-Macedonian interests.