Olympias II of Epirus
Olympias (in Greek Ὀλυμπιάς, ; lived 3rd century BC) was a queen consort and regent of Epirus. She was the daughter of Pyrrhus, king of Epirus and his first wife Antigone. She was the wife of her own paternal half-brother Alexander II. After Alexander's death around 242 BC, she assumed the regency of the kingdom on behalf of her two sons, Pyrrhus II and Ptolemy; and in order to strengthen herself against the Aetolian League she gave before 239 BC her daughter Phthia in marriage to Demetrius II, king of Macedonia. By this alliance, she secured herself in the possession of the sovereignty, which she continued to administer till her sons were grown to manhood, when she resigned it into the hands of Pyrrhus II. But the deaths of Pyrrhus II (circa 238) and his brother Ptolemy (circa 235) followed in quick succession, and Olympias herself died of grief for her double loss, according to Justin. By another account Olympias had poisoned a Leucadian damsel named Tigris, to whom her son Pyrrhus was attached, and was herself poisoned by him in revenge. References
Smith, William (editor); Dictionary of Greek and Roman Biography and Mythology, "Olympias (2)", Boston, (1867)

Notes

Ancient Greek regents
Ancient Greek queens consort
Year of birth unknown
Year of death unknown
3rd-century BC Greek people
Deaths by poisoning
Murdered royalty
3rd-century BC women regents