Castor and Pollux horse breaker and the boxer / Polydeuces, my brothers" ..." – Helen, "Iliad" 3.253–255), but in the "Odyssey" they are treated as alive even though "the corn-bearing earth holds them". The author describes them as "having honour equal to gods", living on alternate days because of the intervention of Zeus. In both the "Odyssey" and in Hesiod, they are described as the sons of Tyndareus and Leda. In Pindar, Pollux is the son of Zeus while Castor is the son of the mortal Tyndareus. The theme of ambiguous parentage is not unique to Castor and Pollux; similar characterisations appear in
Leda and the Swan (Leonardo) Leda and the Swan (Leonardo) The story of Leda and the Swan was the subject of two compositions by Leonardo da Vinci from perhaps 1503–10. Neither survive as paintings by Leonardo, but there are a number of drawings for both by him, and copies in oils, especially of the second composition, where Leda stands. Leonardo began making studies in 1504 for a painting, apparently never executed, of Leda seated on the ground with her children. Three sketches of Leda by Leonardo exist: A completed copy of "Leda and her Children" by Giampietrino is kept at Staatliche Museen, Kassel (c.1520, oil