Polybus of Corinth
Polybus reigned over the city like a gentle man and loved his wife, but unfortunately their marriage remained childless for many years. When Oedipus as an infant was abandoned by his parents Laius and Jocasta, the rulers of Thebes, Periboea who was washing garments at the shore, found and rescued him. In some accounts, either shepherds or keepers of horses of Polybus found the small child in Mount Cithaeron and brought it to Periboea or Laius' household slaves who were unwilling to expose the child gave it as a present to the wife of Polybus, since she could bear no children. With Polybus' consent, since they were childless, they adopted and raised him as their own son, and after his wife had healed the child's ankles, Periboea called him Oidipus, giving him that name on account of his swollen feet caused by injuries in his ankles. A few years later, Periboea became pregnant herself and gave birth to a daughter Alcinoe to Polybus.
After Oedipus had come to manhood, he was courageous beyond the rest and excelled his fellows in strength, and through envy his companions taunted him with not being Polybus' son, since Polybus was so mild, and himself was so assertive. The young man inquired of Periboea about the truth, but could learn nothing from her and so, feeling that the taunt was true, he set out for Delphi and consulted about his true parents. The god told him not to go to his native land because, "You shall kill your father and marry your mother". On hearing that, obviously horrified and disgusted with such a prophecy, Oedipus imposed self-exile upon himself and kept away from Corinth, as he resolved never to murder King Polybus, who had been a kind father to him. Believing himself to be the son of his nominal parents, Oedipus was also understandably disgusted the act of murdering Polybus and claiming his wife for himself, as he had no unnatural attraction to Queen Merope. While riding in a chariot through Phocis he fell in with Laius driving in a chariot in a certain narrow road. When Laius in a disdainful manner ordered Oidipus to make way for him, the latter in anger slew Laius, not knowing that he was his father.
Many years later, after Oedipus won the kingship of Thebes by defeating the Sphinx, did another plague befall Thebes. King Oedipus, in his effort to find the cause of plague due to a patricide, revealed that he was told in his teen years that he was destined to murder his father, and sent a spy to Corinth to see who is currently on the throne. The news of Polybus' death by natural causes was announced by the messenger to Jocasta in Sophocles' Oedipus Rex, in which it is mistakenly taken to mean that Oedipus did not kill his father. This would mean that the prophecy that Oedipus would murder his father and marry his mother would be false, and Oedipus expresses relief that he did not commit such a heinous act. Since Polybus was in fact his adoptive father, Oedipus could and did kill his true father, King Laius, and fulfill the prophecy. Oedipus never knew his true destiny until the final parts of the play.