Ancient Greek authors tell a number of versions of the story of Castor and Pollux. Homer portrays them initially as ordinary mortals, treating them as dead in the Iliad (... there are two commanders I do not see, / Castor the 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 the stories of Hercules and Theseus. The Dioscuri are also invoked in Alcaeus' Fragment 34a, though whether this poem antedates the Homeric Hymn to the twins is unknown. They appear together in two plays by Euripides, Helen and Elektra.