The Minotaur was the son of King Minos' wife, Pasiphae, who was raped by Zeus who came up in the form of a white bull rising from the sea . The monster was sealed away in a labyrinth, and fed live sacrifices in the form of tribute from the shores of Mycenaean Greece. Theseus was the son of Aegeus, King of Mycenae, He was brought to the labyrinth in a black-sailed ship as a sacrifice. But Ariadne, the daughter of Minos, fell in love with Theseus, and gave him two gifts: a sword with which to slay the Minotaur, and a length of golden thread as a means to find his way out of the labyrinth. In return for saving him, Theseus promised to take Ariadne back to Mycenae with him. But having duly despatched the monster Theseus fled without her. But in his haste, he forgot to take down the black sails, and spying these from the headland Aegeus assumed the mourning sails meant that his son was indeed dead, and in his grief he caste himself into the sea and drowned. Thus Theseus was punished - for he in his falsehood had become the monster.
I love myths such as these, for they have so many connotations. There is indeed a labyrinth in the ruins of the Minoan capital, and for a time the Minoan Civilisation dominated the Mediterranean. And the Minoans worshipped the bull as a deity.
So myth invariably has a basis in historical fact.
But there is also both a moral and a psychological underpinning as well. The psychoanalyst C.K.G.Jung argued that each of us has the potential to be the hero of our own lives - and in order to do so we must be courageous. But the risk is that instead of transcending our limitations, we become the monster.
For those who are interested in comparative mythology, and how the active principle of Myth shapes our understanding of the world, I recommend the works of Joseph Campbell, especially The Masks of God and The Hero with a Thousand Faces.
linky: http://en.wikipedia.org/wiki/Joseph_Campbell