As Jocasta makes a sacrifice to Apollo, a messenger arrives to announce the death of Polybus. Oedipus rejoices at the news that the father he feared he would kill has died of natural causes, but he continues to worry about the prophecy because his mother still lives.
Overhearing Oedipus, the messenger tells the king that he has nothing to worry about, since Polybus and Merope were not his real parents. This news stuns Oedipus, and he awaits the shepherd to learn the truth of his birth.
Jocasta now realizes that Oedipus is the baby she and Laius abandoned, and that the prophecy has come true. She begs Oedipus to stop his inquiry, but he refuses, and she runs into the palace screaming.
