Oedipus and the Sphinx.
When Oedipus arrived at Thebes, he found it beseiged by the Sphinx, a winged lion with the head of a woman. She destroyed all those who could not solve her riddle: “What walks on four legs in the morning, two legs at noon, and three legs in the evening?” No one had escaped until Oedipus responded, “Man, who first crawls, then walks upright, then leans on a staff in old age.” The Sphinx, either killed herself in a fury or was slain by Oedipus. As a reward for ridding the city of the Sphinx, he became king of Thebes and married Jocasta, the widowed queen. Such is the heroic state in which King Oedipus finds himself at the start of Sophocles' iconic tragedy.


      See also: Oedipus and Oedipus at Colonus