In Greek mythology, Oedipus first saved the city of Thebes from a plague placed upon it by the Sphinx. He did not defeat the Sphinx through brute force but through intellect when he correctly answered the monster's riddle. He was pronounced King of Thebes but unknowingly married his mother, Jocasta.
The Sphinx had been terrorizing Thebes for an undisclosed amount of time before Oedipus was able to defeat it. The Sphinx placed a great plague over Thebes and refused to remove it until someone correctly answered its riddle. Many heroes attempted to answer the riddle, but each one was eaten alive after answering incorrectly. When Oedipus answered the Sphinx correctly, the Sphinx killed itself.
King Laius received an oracle before Oedipus' birth claiming that a male child produced by Laius would kill him. After Oedipus' birth, Laius sent the newborn to be exposed, but Oedipus was taken to Corinth and raised by the king and queen instead. Oedipus visited an oracle when he was older and was told that he would kill his father and have children with his mother. When he fled, he ran into Laius, who was disrespectful, so Oedipus killed him. Oedipus followed the road to Thebes, where he solved the riddle.