Battle of Ipsus

Lore & Background

The Battle of Ipsus was the culmination of the Fourth War of the Diadochi, fought in 301 BC near the town of Ipsus in Phrygia. The aging Antigonus I Monophthalmus, ruler of large parts of Asia, and his son Demetrius faced a coalition of three other successors: Cassander of Macedon, Lysimachus of Thrace, and Seleucus I Nicator of Babylonia and Persia. The principal ancient source for the period is Diodorus Siculus, whose Library of history provides the only continuous narrative of the Diadochi, though his account of the battle itself survives only in fragments. Plutarch’s Life of Demetrius, written some four centuries later, offers the only full description of the fighting, though it lacks great detail. In the years before the battle, Antigonus had been left in undisputed control of Asia Minor, Syria, and the eastern satrapies after the Second War, alarming the other successors. This led to the Third War, which ended in a compromise peace in 311 BC. Antigonus then attacked Seleucus, resulting in the Babylonian War (311–309 BC), which ended in Antigonus’s defeat and Seleucus reclaiming Babylonia. The Fourth War began in 308 BC when Antigonus resumed conflict with Ptolemy. Demetrius took Athens in 307 BC and defeated Ptolemy’s fleet at Salamis-in-Cyprus. After a failed invasion of Egypt in 306 BC, Demetrius besieged Rhodes in 305 BC, eventually reaching a compromise. He then campaigned in Greece in 303–302 BC, expelling Cassander’s garrisons. Cassander, seeing his power threatened, allied with Lysimachus and sent envoys to Ptolemy and Seleucus. Lysimachus crossed into Asia Minor in 302 BC, taking several cities, while Cassander faced Demetrius in Thessaly.

Reader's Guide

The principal ancient source for the battle is Diodorus Siculus, whose account becomes fragmentary at the year of the engagement, though he provides extensive details on the preceding Fourth War of the Diadochi. Plutarch’s Life of Demetrius, written four centuries later, offers the only surviving full description of the fighting itself, though Plutarch prioritizes moral lessons over tactical depth. The conflict arose from the ambition of Antigonus I Monophthalmus, who controlled Asia Minor, Syria, and the eastern satrapies after the Second War of the Diadochi. His growing power alarmed the other successors—Cassander of Macedon, Lysimachus of Thrace, and Seleucus of Babylonia and Persia—who formed a coalition against him. In the prelude, Lysimachus crossed the Hellespont in 302 BC, taking Lampsakos and Parion, storming Sigeion, and sending Prepelaus to attack Aeolis and Ionia while he besieged Abydos. Cassander simultaneously moved into Thessaly to confront Demetrius, who had been liberating Greek cities from Cassander’s garrisons. The battle’s significance lies in its role as the decisive clash of the Diadochi, leading to the fragmentation of Alexander’s empire into distinct Hellenistic kingdoms.

Did You Know?

• The only full description of the battle is in Plutarch's Life of Demetrius, written some 400 years after the event.
• Diodorus Siculus's account of the battle only exists in fragments from book XXI onwards.
• Hieronymus of Cardia, a contemporary and possible eyewitness, is thought to be Diodorus's source for much of this period.