Other As Antipater grew close to death in 319 BC, he transferred the regency of Macedon not to Cassander, but to
Polyperchon, possibly so as not to alarm the other Diadochi through an apparent move towards dynastic ambition, but perhaps also because of Cassander's own ambitions. Cassander rejected his father's decision, and immediately went to seek the support of
Antigonus,
Ptolemy and
Lysimachus as his allies. Waging war on Polyperchon, Cassander destroyed his fleet, put Athens under the control of
Demetrius of Phaleron, and declared himself Regent in 317 BC. After
Olympias’ successful move against
Philip III later in the year, Cassander besieged her in
Pydna. When the city fell in the spring of 316, Olympias was killed, and Cassander had Alexander IV and
Roxana confined at
Amphipolis. Cassander had Alexander IV and
Roxana secretly poisoned in either 310 BC or the following year. By 309 BC, Polyperchon had begun to claim that
Heracles of Macedon was the true heir to the Macedonian inheritance, at which point Cassander bribed Polyperchon to kill the boy, promising him an alliance and the return of his Macedonian estates. After this, Cassander's position in Greece and Macedonia was reasonably secure, and he proclaimed himself king in 305 BC.
Diodorus Siculus relates that Cassander, Ptolemy, and Lysimachus declared their kingships in response to the assumption of royal title by Antigonus, following his victory over Ptolemy at
Salamis in 306. In 307–304 BC he fought the so-called Four–Years' War against Athens. In 304 BC, his rival
Antigonus Monophthalmus sent his son
Demetrius Poliorcetes to aid Athens against Cassander. Demetrius succeeded in driving Cassander from central Greece and created a Hellenic League,
the League of Corinth, against him. In the winter of 303–302 BC, Cassander opened negotiations with Antigonus with a view to establish peace, but Antigonus refused. At this Cassander turned to Lysimachus, Ptolemy, and
Seleucus and convinced them to reform the coalition of 314–311 against Antigonus. Lysimachus and Prepalaus had been very successful in Asia-Minor and Seleucus was marching with an army to join them. In the spring of 302 BC, Antigonus marched with an army from Syria into Asia-Minor to confront his enemies; he confronted Lysimachus and drove him from
Phrygia. Antigonus realizing that the war would probably have to be decided in a major battle in Asia-Minor recalled Demetrius from Thessaly. With Demetrius gone Cassander sent part of his army with his brother,
Pleistarchus, to join Prepalaus, Lysimachus and Seleucus in Asia-Minor. Cassander's dynasty did not live much beyond his death, with his son
Philip dying of natural causes, and his other sons
Alexander and
Antipater becoming involved in a destructive dynastic struggle along with their mother. When Alexander was ousted as joint king by his brother,
Demetrius I took up Alexander's appeal for aid and ousted Antipater, killed Alexander V and established the
Antigonid dynasty. The remaining Antipatrids, such as
Antipater II Etesias, were unable to re-establish the Antipatrids on the throne. == Legacy ==