While the Hellenistic Kingdoms (the inheritors of Alexander the Great) were fighting each other and the Galatians, Rome became the most powerful state in Europe and started to follow a policy of expansion to the east. The Romans invaded Macedon, Thrace, and the Dardanelles, reaching Phrygia via Magnesia and Pisidia. They cowed the Galatians and according to the treaty, signed in 188 BC in Apamea, after they got the land of Pisidia from Antiochos III, they gave it to their ally, the Kingdom of Pergamon, the dominant power in the region. Attalos III, the last king of Pergamon, bequeathed his kingdom to Rome on his death in 133 BC. When Aristonikos, a usurper who claimed the throne of Pergamon shortly after, was defeated in 129 BC, Rome annexed and populated Western Anatolia with its well-developed, creative culture, lasting for centuries.