The town was the basic political unit in the Helladic area during the classical era. In the Hellenistic and Roman periods, many towns, especially in mainland Greece, suffered heavily from the wars of conquest of the Romans and then from the civil fights of the late years of the Republica. In the Greek mainland, Patras, Corinth and Nikopolis, all Roman colonies, were the only towns that prospered. Athens and Sparta, on the contrary, became a shadow of their glorious past, functioning as centres of a peculiar cultural tourism. The transformation of the Greek town from an autonomous state to a part of the Roman Empire is certified by the changes observed in the architectural function of its public buildings.