Aiakid princess of Epirus (born c. 375 BCE as Polyxena, daughter of Neoptolemus I); queen consort of Philip II of Macedon (married c. 357 BCE, after meeting at the Samothrakian mysteries); mother of Alexander the Great (born 356 BCE) and Cleopatra of Macedon. Through her Aiakid descent, Olympias traced ancestry from Neoptolemos son of Achilles, through Aeacus, to Zeus — making Alexander on his mother's side already a scion of the Olympian line by recognized Greek-aristocratic genealogical convention. Devoted to Dionysian and orphic mystery-cults; known for handling tame snakes in ecstatic processions. The serpent-impregnation narrative (Plutarch, Alexander 2-3): the night before her marriage was consummated, dreamed a thunderbolt struck her womb and fire spread from it; subsequently Philip observed a serpent lying alongside her on her bed and consulted the oracle of Zeus at Dodona, which warned him to honor Zeus-Ammon and that the serpent was a divine impregnator. Olympias herself sustained the Zeus-Ammon paternity claim through Alexander's lifetime; the 332 BCE Siwa Oracle's recognition of Alexander as son of Zeus-Ammon canonized it. Estranged from Philip after his 337 BCE marriage to Cleopatra Eurydice; widely suspected by ancient sources of arranging Philip's assassination at Aegae 336 BCE and the subsequent murder of Cleopatra Eurydice and her infant. Conflicted bitterly with the regent Antipater during Alexander's Asian campaign; defended her grandson Alexander IV in the wars of the Diadochi after Alexander's death; defeated and executed by Cassander 316 BCE at Pydna.