 Oedipus learned from the oracle at Delphi of the prophecy that he would end up killing his father and marrying his mother but, unaware of his true parentage, believed he was fated to murder Polybus and marry Merope, so left for Thebes.On his way he met an older man and killed him in a quarrel.Continuing on to Thebes, he found that the king of the city (Laius) had been recently killed, and that the city was at the mercy of the Sphinx.