King Minos promised his prize bull to Poseidon each year as a sacrifice, however, one year the bull was such a magnificent animal that Minos decided to keep it for himself and sacrifice his second best, hoping that Poseidon would not notice. Posiedon was very angry when he realised what had been done so he caused Minos's wife to be overcome with a fit of madness in which she went to the stables and had sexual intercourse with the bull. The result of this union was the Minotaur.
The Minotaur was finally slain by Theseus whow as sent as part of the tithe to Crete but managed to overcome the Minotaur and escape the labyrinth with the help of Minos's daughter, Ariadne?.