military engagement fought at Ipsus, Phrygia, in 301 BC between two camps of the “successors” (diodochoi) of Alexander the Great, part of a struggle that accelerated the dismemberment of Alexander's empire begun after his death.

In 302 a coalition representing Lysimachus, king of Thrace, Seleucus I Nicator of Babylon, Ptolemy I Soter of Egypt, and Cassander of Macedonia moved against Antigonus I Monophthalmus, king in Asia Minor, and his son Demetrius I Poliorcetes. Although the combined strength of Seleucus and Lysimachus in troops was only slightly inferior to the 70,000 foot soldiers and 10,000 horses of Antigonus, it was the allies' superiority in elephants that proved invaluable for victory. The elephants had been supplied by the Indian potentate Chandragupta (called Sandracottus by the Greeks) in return for Indian land conquered by Alexander the Great; they prevented Demetrius, who had pursued too far after defeating the opposing cavalry, from returning to rescue his father. Antigonus was killed, Demetrius fled, and Asia Minor was added to the dominions of Lysimachus.