Zeus and Leda. She was the wife of Menelaüs, king of Sparta, and later of Paris, son of Priam. Her name in Greek is Helene, and most authorities derive it from hele, 'light', 'heat', although there are good grounds for regarding it as a non-Greek name, but as one associated with birds and trees in some way.
In his Agamemnon, Aeschylus ingeniously relates her name to Helenas, 'ship-destroyer', since she 'took the ships' (helein, 'to take', naus, 'ship'). Her name may go back to Sanskrit sarama, 'born of the sky', fittingly enough for her, since she was the daughter of Zeus.
Whatever the case, the modern girl's name Helen seems to owe its popularity not so much to her but to a more earthly Helen - St. Helena, the mother of the emperor Constantine. But inevitably some of the mythological Helen's charisma and beauty must rub off on modern Helens.