Eventually Cadmus' great-grandson Laius became king at Thebes. Laius married Jocasta, but learned from the Delphic oracle that he would die by the hands of his own child. However, he got drunk one night and conceived a son. Laius and Jocasta exposed the infant on a mountain, riveting its ankles together. The child was found by a Corinthian peasant who took it to the childless King Polybus. Polybus accepted the boy and raised it as his own, naming it Oedipus.
As a young man Oedipus consulted the Delphic oracle, and it told him he would murder his father and marry his mother. Horrified, Oedipus did not return to Corinth, thinking that Polybus and his queen, Merope, were his true parents. Instead he went to Thebes, where a monster called the Sphinx was waylaying travelers and killing everyone who could not answer her riddle. The Sphinx had the body of a lion, the wings of an eagle, and the head and chest of a woman. When Oedipus confronted her she asked him what creature walks on four legs in the morning, two legs at noon, and three legs at evening. Oedipus answered, "Man," realizing the riddle referred to man's progress from infancy to old age. The Sphinx then killed herself, and the Thebans welcomed Oedipus as their king for having delivered them.
He married Queen Jocasta and fathered two sons and two daughters on her. Thebes flourished under King Oedipus. But then a plague struck the city, decimating the inhabitants. Pledged to aid the city, Oedipus sent his brother-in-law Creon to the Delphic oracle to learn how the plague might be stopped. The oracle said that the person who had killed King Laius years before must be caught and punished. Oedipus vowed to find the culprit and summoned the seer Teiresias to name the guilty one. At first Teiresias was silent, but goaded by the king he revealed that Oedipus himself was Laius' killer. Angered and dumbfounded, Oedipus inquired about the whereabouts of Laius' death, which had occurred near Delphi where three roads met. Oedipus recalled killing an arrogant old man and his retinue who had assaulted him in that very place. Of course it was Laius he had slain. Then a messenger arrived to tell Oedipus that King Polybus had died and left Oedipus the kingdom of Corinth. Presently the facts came out that Polybus was not Oedipus' real father and that Oedipus had been found exposed on a mountain. Jocasta grew distraught and pleaded with her husband to abandon his investigation. And at last the truth dawned on Oedipus that he had indeed murdered his father and married his mother. In despair Jocasta hanged herself, while Oedipus blinded himself in an agony of remorse. Wishing to be killed or exiled, he gave Thebes to Creon to rule as regent, and Creon promised to care for Oedipus' daughters.
