Who is Teiresias?

Teiresias, the most famous soothsayer of Greece, was born at Thebes. He was the son of Eueres and Chariclo, descendant of Udaeus of Sparti. He was blind and there are many stories for the cause of his blindness. The most wide accepted tradition was that at age seven the Gods blinded him, because he revealed certain things, men ought not to know.According to another tradition, he was blinded after he saw goddess Athena taking bath. Athena threw water in his eyes and thus blinded him. Since his mother, Chariclo was a friend, a nymph of Athena, begged her to undo her curse, but Athena could not; instead of giving him a staff, she cleaned his ears, giving him the ability to understand birdsong, gift of prophecy and a life seven generations long. In another version, he saw snakes coupling and killed one of them with a stick, whereupon he changed into a woman, later the same thing happened again and he changed back into a man. Since he was now uniquely qualified to answer, Zeus and Hera consulted him as to whether a man or a woman derived more pleasure from the act of love. When Teiresias replied that women received nine times as much pleasure as men, Hera struck him blind, but Zeus gave him the gift of unerring prophecy.
In Sophocles's Oedipus The King, the king of Thebes, calls upon Teiresias to aid in the investigation of the killing of the previous king Laius At first, Teiresias refuses to give a direct answer and instead hints that the killer is someone Oedipus really does not wish to find. However, after being provoked to anger by Oedipus' accusation first that he has no foresight and then that Teiresias had a hand in the murder, he reveals that in fact it was Oedipus himself who had (unwittingly) committed the crime. Outraged, Oedipus throws him out of the palace, but then afterwards realizes the truth.