Prior to the start of Oedipus Rex, Oedipus has become the king of Thebes while unwittingly fulfilling a prophecy that he would kill his father, Laius (the previous king), and marry his mother, Jocasta (whom Oedipus took as his queen after solving the riddle of the Sphinx). The action of Sophocles' play concerns Oedipus' search for the murderer of Laius in order to end a plague ravaging Thebes, unaware that the killer he is looking for is none other than himself. At the end of the play, after the truth finally comes to light, Jocasta hangs herself while Oedipus, horrified at his patricide and incest, proceeds to gouge out his own eyes in despair.
The play is thought to have been first performed c. 429 BC, although this is highly uncertain. Although the play won only second place at its initial performance, it was later considered by Aristotle to be one of the greatest Greek tragedies, and is now widely considered one of the greatest plays of Western literature, and the most famous of all Greek tragedies.