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 on the ground with her children. In 1508 he painted a different composition of the subject, with a nude standing Leda cuddling the Swan, with the two sets of infant twins (also nude), and their huge broken egg-shells. The original of this is lost, probably deliberately destroyed, and was last recorded in the French royal Château de Fontainebleau in 1625 by Cassiano dal Pozzo. However it is known from many copies, of which the earliest are probably the "Spiridon Leda", perhaps by a studio assistant and now in the Uffizi, and the one at Wilton House in England (illustrated). Also