Ancient historians provide us a partial, mostly favourable to Rome, picture of the expansion during the Republic. However, not much attention has been devoted to the local economic history of the Greek cities that became part of the Roman state. Thanks to a completely new edition of the financial accounts of the Greek city-state of Tauromenion from the I century B.C., we shed new light on the intertwined process of institutional and economic change in Sicily during the I century B.C. In addition to informing us about the aggregate economic movements of the city, the Tauromenion accounts also show clear signs of Roman influence as months and magistrates were named after the Roman tradition. We find that there was no structural break in the civic accounts associated with this institutional change, but rather that the generally wealthy city of Tauromenion showed signs of financial distress in the last years before the change. The evidence suggests that rather than being an imposition of Rome, institutional change was voluntarily embraced by middle-sized cities such as Tauromenion and could be motivated by economic reasons