LEDA, in Greek mythology, daughter of Thestius, king of Aetolia, and Eurythemis (her parentage is variously given). She was the wife of Tyndareus and mother of Castor and Pollux, Clytaemnestra and Helen (see Castor and Pollux). In another account Nemesis was the mother of Helen (q.v.) whom Leda adopted as her daughter. This led to the identification of Leda and Nemesis. In the usual later form of the story, Leda herself, having been visited by Zeus in the form of a swan, produced two eggs, from one of which came Helen, from the other Castor and Pollux.
See Apollodorus iii. 10; Hyginus, Fab. 77; Homer, Iliad, iii. 426, Od. xi. 298; Euripides, Helena, 17; Isocrates, Helena, 59; Ovid, Heroides, xvii. 55; Horace, Ars poetica, 147; Stasinus in Athenaeus viii. 334 c.; for the representations of Leda and the swan in art, J. A. Overbeck, Kunstmythologie, i., and Atlas to the same; also article in Roscher’s Lexikon der Mythologie.