The most usual account, however, is that it was Leda herself with whom Zeus companied in the form of a swan beside the river Eurot: that she laid an egg from which were hatched Helen, Castor, and Polydeuces; and that she was consequently deified as the goddess Nemesis. Now, Leda’s husband Tyndareus had also lain with her the same night and, though
some hold that all these three were Zeus’s children—and Clytaemnestra too, who had been hatched, with Helen, from a second egg—others record that Helen alone was a daughter of Zeus, and that Castor and Polydeuces were Tyndareus’s sons; some others again, that Castor and Clytaemnestra were children of Tyndareus, while Helen and Polydeuces were children of Zeus.