Hylas and the Nymphs, 1896, John William Waterhouse.

In classical mythology, Hylas  was a youth who served as Heracles' (Roman Hercules) companion and servant. His abduction by water nymphs was a theme of ancient art, and has been an enduring subject for Western art in the classical tradition. After Heracles killed Theiodamas in battle, he took on Hylas as arms bearer and taught him to be a warrior. The poet Theocritus (about 300 BC) wrote about the love between Heracles and Hylas: "We are not the first mortals to see beauty in what is beautiful. No, even Amphitryon's bronze-hearted son, who defeated the savage Nemean lion, loved a boy—charming Hylas, whose hair hung down in curls. And like a father with a dear son he taught him all the things which had made him a mighty man, and famous."

Heracles took Hylas with him on the Argo, making him one of the Argonauts. Hylas was kidnapped by nymphs of the spring of Pegae, Mysia when they fell in love with him, and he vanished without a trace (Apollonios Rhodios). This greatly upset Heracles, so he along with Polyphemus searched for a great length of time. The ship set sail without them. According to the Latin Argonautica of Valerius Flaccus, they never found Hylas because the latter had fallen in love with the nymphs and remained "to share their power and their love." Theocritus, on the other hand, has the nymphs shutting his mouth underwater to stifle his screams for Heracles.