The royal couple adopted a baby found by shepherds and named him Oedipus. To avoid the prediction of an oracle that he will kill his father and marry his mother, Oedipus goes in voluntary exile to Thebes. On his way he has a quarrel with an old man, and kills him, and for answering a riddle of the Sphinx at the entrance of Thebes gets to marry the queen dowager Jocasta. He fathers four children with Jocasta: Polynices, Eteocles, Antigone, and Ismene. He eventually finds out that the old man whom he killed on his way to Thebes was his own biological father, King Laius, husband of Jocasta, and that he fulfilled the prophecy.