When the play 'Oedipus the king' begins, the audience sees that the chorus consisting of the elders in Thebes have come to their leader asking him to find out the reason why Thebes is suffering once again from a plague. Oedipus, in the meanwhile, has already sent his brother in law Creon to the Oracle at Delphi to find out the reason why Thebes is being punished. Creon returns with the message that the Oracle had proclaimed that there is an unclean being in Thebes, the murderer of the former king, who must be discovered and punished. Oedipus proclaims that he will find this person and expel him from Thebes, even if that person happened to be a member of his own household. This foreshadows later events. However it is ironic, because Oedipus does not realize that he has proclaimed an edict against himself, for he is the unclean being who has, unwittingly, murdered the former king, his father and married the widow of the king, his own mother.