King Laius tries to dispose of Oedipus once he hears that he son will later kill him.
the servant he sent to Oedipus could not do it. Instead, he was left on the mountain, found by a herdsman, and raised by the King and Queen of Corinth.
Oedipus hears a rumor that he might be adopted so he goes to the prophet Tiresias to find out. Tiresias doesn't tell him about that, but instead tells him that he will kill his father and marry his mother.
Not knowing the truth and still believing the King and Queen of Corinth to be his real parents, he leaves the city. At a crossroad, he meet King Laius (who harasses him) so Oedipus kills him.
Oedipus arrives in Thebes and finds that it is being terrorized by a Sphynx. It will only leave after it's riddle is answered. Oedipus accepts the challenge, answers it correctly, and saves Thebes
Saving the city earned him the Queen's hand in marriage.