In Greek mythology, Tiresias was a blind prophet of Apollo who had the gift of clairvoyance (the reason how he got it varies). According to Pliny the Elder, Tiresias is credited for starting the study of augury (interpreting an omen by observing the behavior of birds).

Early in his life, Tiresias encounter two mating snakes. For whatever reason, he struck them with his walking stick, causing the goddess Hera to change his gender! More information will be given of this later when I make a female version of Tiresias. After seven years, Tiresias was changed back into a man, and went about his life normally.

Like his clairvoyance, there are different sources about how he was blinded, with one story involving him accidentally offending Hera (again), only this time, Zeus gifted Tiresias with prophecy. Another story has him accidentally witnessing a naked Athena, which also resulted in the goddess blinding him, but as pity, gave him foresight. He eventually becomes the oracle of Thebes.

In Oedipus Rex, Tiresias is brought in by the titular king to investigate the "mysterious" death of the previous king, Laius. Tiresias, gifted with foresight, knew the answer, and refused to fully explain, until Oedipus accuses him of taking part in the murder. Eventually, Tiresias tells the truth, and though Oedipus is offended by the answer at first, he would eventually learn he was being told the horrible truth.

Tiresias died after he drank from the water of Tilphussa. In the Odyssey, sometime after his death, the hero Odysseus ventured to the underworld to seek advice from Tiresias about how he should make his way home. The spirit of Tiresias told Odysseus how he should sail between the sea monsters - Scylla and Charybdis - and also warns him not to sacrifice and eat the sacred cattle of Helios (Odysseus' men wouldn't follow this advice, which would eventually cause Zeus to destroy the entire ship, leaving Odysseus the sole survivor).

And finally, in the Inferno - the first canticle of Dante Alighieri's Divine Comedy - Tiresias is punished in the fourth area of Hell's eighth circle, Fraud. Because he was a magician who - though blind - could see into the future, Tiresias has his head twisted backwards as punishment. Dante really didn't like the Greeks that much.