born 308, Cos
died 246 BC
King of Egypt (285246 BC), second king of the Ptolemaic dynasty.
He reigned as coruler (285282) with his father, Ptolemy I Soter , then purged his family of rivals, including his first wife, and married his sister, Arsinoe II . Wars with the rulers of the Seleucid and Antigonid dynasties weakened his influence in the Aegean and brought near-disaster to his allies Athens and Sparta. He concluded these wars by diplomacy and marriage alliances and managed to regain his influence in the Aegean. He devised a buffer zone of possessions to protect Egypt from attack, and he dealt with reverses through diplomacy. A prudent and enlightened ruler, he promoted economic development and made Alexandria into a centre for poets and scholars.