But there were other stories about the birth of Romulus and his brother Remus. The story of Romulus' divine origin says that his mother was the mortal daughter of Aeneas and Lavinia, and his father was Mars. In his "Hymn to Asclepius", Homer attributes his origin to the god Apollo and the daughter of a renowned soldier, King Phlegyas. As the divine patron of the healing art, Asclepius became the most popular of the hero gods of Greece. The belief that religion was concerned with sickness and disease was central to his cult. His sanctuaries in the Greco-Roman world became so famous there was a movement to make him a god of the first rank and identify him with Zeus himself. Asclepius was "the one who leads and controls all things, the savior of the whole world, and the guardian of mortals." Helen of Troy was worshiped as a heroine in several parts of the ancient world during the early historical epoch. Euripides' play "Helen" depends on a tradition begun in the early 6th century B.C. by the Greek poet Stesichorus that Helen was the daughter of Zeus (who took the form of a swan) and Leda. But this might simply be a poetic way of saying that she was hatched from an egg. There are two versions of the birth of Oedipus. He was given a semidivine status in Sophocles' "Oedipus the King," where he was said to be the son of either Pan, Loxias, "or the Bacchants' god, dweller on the hilltops ..." and one of the nymphs of Helicon. But in Euripides' "Phoenissae," his mother, Jocasta, says Oedupus is the son of Laius, a mortal, who was warned by the god Phoebus not to have children. "King of Thebes for horses famed! seek not to beget children against the will of heaven; for if thou beget a son, that child will slay thee, and all thy house shall wade in blood." Laius ignored the warning, but after the child was born he gave him to shepherds to expose on Mount Cithaeron. The child was found and raised among the keepers of the horses of Polybus. As a grown man, Oedipus did indeed kill his father, not realizing who he was, and then married his mother.