The death of Alexander the Great in 323 BC unleashed all the forces that only his powerful personality had kept in check. After twenty years of bitter conflict the vast empire of the great conqueror had been divided into warring kingdoms. At the same time, the Celtic tribes had spread over most of central and western Europe. The actions of Philip and Alexander had limited the Celts to the area north of the Danube, but after Alexander’s death the Celts subdued the Thracians who lived to the south of the great river. However, Lysimachus and the Paeonians continued to limit their expansionist appetite.
In the second decade of the third century, the situation seemed to have stabilized in the kingdoms of the successors of Alexander; in Macedonia the Antigonids had been neutralized, Seleucus held Syria, Lysimachus Thrace, and Ptolemy Egypt. The
