In Greek mythology, Hermione (;Greek: ? [hermi.ón?:]) was the only child of Menelaus, king of Sparta, and his wife, Queen Helen.  Prior to the Trojan War, Hermione had been betrothed by Tyndareus, her grandfather, to her cousin Orestes, son of her uncle, Agamemnon; she was just nine years old when Paris, son of the Trojan king Priam, arrived to abduct her mother, Helen.
During the war, Menelaus promised her to Achilles' son, Neoptolemus. and after the war ended, he sent Hermione away to the city of Phthia (the home of Peleus and Achilles), where Neoptolemus was staying. The two were married, yet, soon afterwards, Neoptolemus traveled to Delphi in order to exact vengeance against Apollo for having caused his father's death, only to be shot down by the god's arrow. With Neoptolemus dead, Hermione was free to marry Orestes, after which she bore him a son, Tisamenus.
Ancient poets disagree over whether Menelaus was involved in both betrothals. Euripides has Orestes say:
?Because, in fact, you were rightfully mine, from a long time ago. Your father has promised you to me before he left for Troy but then, the liar that he is, when he got to Troy, he offered you to Neoptolemos, your present husband, if he, in return captured the city?.-- Andromache 969, translation by George Theodoridis
Ovid, on the contrary, says that Menelaus did not even know of the promise made by Tyndareus:
(Hermione) "Tyndareus gave me to you, he, my ancestor, heavy with experience,
and years: the grandfather decided for the grand-child.
But Menelaus, my father, made a promise of me, unaware of this act."
giving a marriage feast to his many kinsfolk for his noble son and daughter within his house. His daughter he was sending to the son of Achilles, breaker of the ranks of men, for in the land of Troy he first had promised and pledged that he would give her, and now the gods were bringing their marriage to pass.-- Odyssey IV, 3-7, translation by A. T. Murray (Loeb edition)
Shortly after settling into the domestic life, conflict arose between Hermione and Andromache (widow of Hector, prince of Troy and elder brother of Paris), the concubine Neoptolemus had obtained as a prize after the sack of Troy. Hermione blamed Andromache for her inability to become pregnant, claiming that she was casting spells on her to keep her barren. She asked her father to kill Andromache while Neoptolemus was away at war, but when he chose not to go through with the murder, Hermione fled from Epirus with her cousin Orestes.
Hermione and Orestes were married, and she gave birth to his heir Tisamenus. The myths do not mention Hermione after that, though it is said that Orestes later married his half-sister Erigone, daughter of Clytemnestra and Aigisthus, who was Orestes' second cousin.
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