Also called the Asterion, it was a half-man, half-bull monster kept in the Labyrinth on Crete by King Minos. Minos prayed to Poseidon to send a snow-white bull as a sign of support during Minos' quarrel with his brothers for the throne of Crete, but instead of sacrificing the animal to the sea god, Minos kept it for himself. Angered, Poseidon caused Minos' wife Pasiphaë to lust after the bull, so Daedalus built her a wooden cow so she could mate with the bull. The product of this encounter was the Minotaur (lit. 'Bull of Minos'). After Minos' son Androgeus was killed by Athenians, Minos demanded seven Athenians male youths and seven Athenian female youths, to be selected by lots every seven or nine years (accounts vary) as retribution; these victims were fed to the Minotaur. On the third drawing of the lots, the Athenian hero Theseus volunteered to vanquish the beast; with the help of Minos' daughter Ariadne, who gave Theseus a ball of string so he could find his way out of the Labyrinth, Theseus slew the Minotaur. On the return voyage from Crete, Theseus forgot to change his sails from black back to white, and his father Aegeus jumped into the sea, believing his son had died.