The beginning of Hellenistic Greece was defined by the struggle between the
Antipatrid dynasty, led first by
Cassander (r. 305 – 297 BC), son of
Antipater, and the Antigonid dynasty, led by
Antigonus I Monophthalmus (r. 306 – 301 BC) and his son, the future king
Demetrius I Poliorcetes (r. 294 – 288 BC). After the power crisis in Macedon, which culminated in
Philip III's and
Euridice's death, Cassander managed to seize control from
Olympias and began to establish his authority in the kingdom; in 316 BC he buried Philip III and Euridice at
Aegae and married
Philip II's daughter,
Thessalonica, thus becoming a member of the Argead dynasty. In 310/309 BC, Cassander commanded
Glaucias to secretly assassinate the 14-year-old
Alexander IV, son of Alexander the Great, and his mother
Roxane and the Macedonian Argead dynasty became extinct. In 307 BC, Demetrius I successfully ousted
Cassander's governor of
Athens,
Demetrius of Phalerum, and after defeating
Ptolemy I at the
Battle of Salamis in 306 BC he conquered the island
Cyprus. Following that victory, Demetrius' father, Antigonus I, assumed the title of
Basileus ("King" of Alexander's Empire) by the assembled armies and gained control over the Aegean, the eastern Mediterranean, and most of the Middle East. Demetrius I survived the battle and in 294 BC –during the struggles between Casander's sons
Alexander V and
Antipater I– he managed to seize control of Athens and establish himself as king of Macedon. In 288 BC, he was driven out by
Pyrrhus and Lysimachus and eventually died as a prisoner of Seleucus I Nicator. After a long period of instability, Demetrius' son
Antigonus II Gonatas was able to establish the family's control over the old Kingdom of Macedon, as well as over most of the Greek city-states by 276 BC. ==Legacy==