Idyll XIII, sometimes called Ύλας ('Hylas'), is a bucolic poem by the 3rd-century BC Greek poet Theocritus. As in Idyll XI, Nicias is again addressed, by way of introduction to the story of Hylas. This beautiful lad, a favourite companion of Heracles, took part in the Quest of the Fleece of Gold. As he went to draw water from a fountain, the water-nymphs dragged him down to their home, and Heracles, after a long and vain search, was compelled to follow the heroes of the Quest on foot to Phasis.