Battle of Ipsus - Background

Background

In the aftermath of the Second War of the Diadochi (315 BC), the ageing satrap Antigonus Monophthalmus had been left in undisputed control of the Asian territories of the Macedonian empire (Asia Minor, Syria and the vast eastern satrapies). This left Antigonus in prime position to claim overall rule over the Macedonian empire. Antigonus's growing power alarmed the other major Successors, resulting in the eruption of the Third War of the Diadochi in 314 BC, in which Antigonus faced a coalition of Cassander (ruler of Macedonia), Lysimachus (ruler of Thrace) and Ptolemy (ruler of Egypt). This war ended in a compromise peace in 311 BC, after which Antigonus attacked Seleucus, who was attempting to re-establish himself in the eastern Satrapies of the empire. The resulting Babylonian War lasted from 311-309 BC, and resulted in deafeat for Antigonus, allowing Seleucus to re-claim the satrapy of Babylonia and overlordship of the territories to the east.

While Antigonus was distracted elsewhere, Ptolemy had been expanding his power into the Aegean Sea and to Cyprus. Antigonus thus resumed the war with Ptolemy in 308 BC, beginning the Fourth War of the Diadochi. Antigonus sent his son Demetrius to regain control of Greece, and in 307 BC he took Athens, expelling the Demetrius of Phaleron, Cassander's governor, and proclaiming the city free again. Demetrius then turned his attention to Ptolemy, invading Cyprus and defeating Ptolemy's fleet at the Battle of Salamis-in-Cyprus. In the aftermath of this victory, Antigonus and Demetrius both assumed the crown of Macedon, in which they were shortly followed by Ptolemy, Seleucus, Lysimachus, and eventually Cassander.

In 306, Antigonus attempted to invade Egypt, but storms prevented Demetrius's fleet from supplying him, and he was forced to return home. With Cassander and Ptolemy both weakened, and Seleucus still occupied by attempting to assert his control over the East, Antigonus and Demetrius now turned their attention to Rhodes, which was besieged by Demetrius's forces in 305 BC. The island was reinforced by troops from Ptolemy, Lysimachus, and Cassander. Ultimately, the Rhodians reached a compromise with Demetrius – they would support Antigonus and Demetrius against all enemies, save their ally Ptolemy. Ptolemy took the title of Soter ("Savior") for his role in preventing the fall of Rhodes, but the victory was ultimately Demetrius's, as it left him with a free hand to attack Cassander in Greece. Demetrius thus returned to Greece at set about liberating the cities of Greece, expelling Cassander's garrisons, and the pro-Antipatrid oligarchies. This occupied much of Demetrius's efforts in 303 and 302 BC.

Seeing that Demetrius's war effort was aimed at destroying his power in Greece, and ultimately in Macedonia, Cassander tried to come to terms with Antigonus. However, Antigonus rejected these advances, intent on forcing Cassander's complete surrender. Cassander therefore held counsel with Lysimachus, and they agreed on a joint strategy that included sending envoys to Ptolemy and Seleucus, asking them to join in combatting the Antigonid threat. Seeking to take the initiative, Cassander sent a significant portion of the Macedonian army under Prepelaus to Lysimachus, which was to be used in joint operations in Asia Minor. Meanwhile, Cassander took the rest of the Macedonian army into Thessaly to confront Demetrius.