Leda was the daughter of King Thestius and Eurythemis, sister of Althea, Hypermnestra, Iphiclus, Euippus, Plexippus and Eurypylus, wife of Tyndareus, mother of the Dioscuri Castor and Polydeuces, Helen the Fair, Philonoe, Clytemnestra and Timandra. When Zeus saw Leda in Taygetus he fell in love with her and to conquer her he transformed into a swan with the help of Aphrodite who took the form of an eagle and pursued him.
Leda took a liking to the bird and hugged it to protect it, causing it to lay two eggs, one apparently two-crested, from which came her first three children. Leda then treated the swan as an edible bird, a common occurrence in the animal kingdom.