Answer
Cassander, a Macedonian general, dethroned Pyrrhus four years after he became king. Pyrrhus had ascended to the throne of Epirus in 297 BC, but his reign was short-lived. Cassander, who had been regent of Macedonia during the minority of Alexander the Great's son, Alexander IV, saw Pyrrhus as a threat to his power. In 293 BC, Cassander invaded Epirus and defeated Pyrrhus, forcing him to flee to the Peloponnese.