Final answer:
The Pythian oracle foresaw that Oedipus would kill his father and marry his mother, a prophecy that Oedipus desperately attempted to avoid, only to inadvertently fulfill it.
Step-by-step explanation:
Before Oedipus became king of Thebes, the Pythian oracle prophesied that he would kill his father and marry his mother.
Upon visiting the Oracle of Delphi, the young Oedipus was horrified to learn of a chilling destiny: he was fated to commit patricide and incest. Striving to circumvent his doomed future, he decided to leave Corinth, the city he believed to be his birthplace. His journey led him, unwittingly, to the events that would fulfill the oracle's grim prophecy.
Oedipus, in a tragic twist of fate, killed his actual father, King Laius, in a dispute at a crossroads and later married his mother, Jocasta, thus becoming the king of Thebes. When the truth emerged, it shattered his world, ultimately leading to both his and Jocasta's tragic undoing.