"as whilom did Hercules that of Hylas"
In classical mythology, Hylas was a youth who served as a companion of Hercules. Roman sources state that Hylas was the son of Hercules and the nymph Melite. He gained his beauty from his divine mother and his military prowess from his demigod father.
While Hercules and Hylas were travelling together, Hylas was abducted by water nymphs of the spring of Pegae. Heracles was distraught, and searched for Hylas for a great length of time. Hylas, however, had fallen in love with the nymphs, and was never found.