When did Oedipus encounter the sphinx?

Oedipus encountered the Sphinx after he had left Corinth, while traveling to Thebes. The Sphinx was terrorizing the city by posing a riddle to its inhabitants, and those who could not solve it were killed. Oedipus successfully answered the riddle, which led to the Sphinx's demise and his eventual ascension to the throne of Thebes. This encounter is a pivotal moment in Sophocles' play "Oedipus Rex."