Eighteen allusions to mythic Tiresias, noted by Luc Brisson, fall into three groups: one, in two episodes, recounts Tiresias' sex-change and his encounter with Zeus and Hera; a second group recounts his blinding by Athena; a third, all but lost, seems to have recounted the misadventures of Tiresias.
Tiresias was a prophet of Apollo. According to the mythographic compendium Bibliotheke, different stories were told of the cause of his blindness, the most direct being that he was simply blinded by the gods for revealing their secrets. An alternate story told by the poet Pherecydes was followed in Callimachus' poem "The Bathing of Pallas"; in it, Tiresias was blinded by Athena after he stumbled onto her bathing naked. His mother, Chariclo, a nymph of Athena, begged Athena to undo her curse, but the goddess could not; instead, she cleaned his ears, giving him the ability to understand birdsong, thus the gift of augury.
On Mount Cyllene in the Peloponnese, as Tiresias came upon a pair of copulating snakes, he hit the pair a smart blow with his stick. Hera was not pleased, and she punished Tiresias by transforming him into a woman. As a woman, Tiresias became a priestess of Hera, married and had children, including Manto, who also possessed the gift of prophecy. According to some versions of the tale, Lady Tiresias was a prostitute of great renown. After seven years as a woman, Tiresias again found mating snakes; depending on the myth, either she made sure to leave the snakes alone this time, or, according to Hyginus, trampled on them. As a result, Tiresias was released from his sentence and permitted to regain his masculinity. This ancient story is recorded in lost lines of Hesiod.
In a separate episode, Tiresias was drawn into an argument between Hera and her husband Zeus, on the theme of who has more pleasure in sex: the man, as Hera claimed; or, as Zeus claimed, the woman, as Tiresias had experienced both. Tiresias replied "Of ten parts a man enjoys one only." Hera instantly struck him blind for his impiety. Zeus could do nothing to stop her, but he did give Tiresias the gift of foresight and a lifespan of seven lives.
Stripped of its narrative, anecdotal and causal connections, the mythic figure of Tiresias combines several archaic elements: the blind seer; the impious interruption of a natural rite (whether of a bathing goddess or coupling serpents); serpents and staff (Caduceus); a holy man's double gender (shaman); and competition between deities.
Tiresias's background, fully male and then fully female, was important, both for his prophecy and his experiences. Also, prophecy was a gift given only to the priests and priestesses. Therefore, Tiresias offered Zeus and Hera evidence and gained the gift of male and female priestly prophecy. How he obtained his information varied: sometimes, like the oracles, he would receive visions; other times he would listen for the songs of birds, or ask for a description of visions and pictures appearing within the smoke of burnt offerings, and so interpret them.
Tiresias makes a dramatic appearance in the Odyssey, book XI, in which Odysseus calls up the spirits of the dead (the nekyia). "So sentient is Tiresias, even in death," observes Marina Warner "that he comes up to Odysseus and recognizes him and calls him by name before he has drunk the black blood of the sacrifice; even Odysseus' own mother cannot accomplish this, but must drink deep before her ghost can see her son for himself".
As a seer, "Tiresias" was "a common title for soothsayers throughout Greek legendary history" (Graves 1960, 105.5). In Greek literature, Tiresias's pronouncements are always gnomic but never wrong. Often when his name is attached to a mythic prophecy, it is introduced simply to supply a personality to the generic example of a seer, not by any inherent connection of Tiresias with the myth: thus it is Tiresias who tells Amphytrion of Zeus and Alcmena and warns the mother of Narcissus that the boy will thrive as long as he never knows himself. This is his emblematic role in tragedy (see below). Like most oracles, he is generally extremely reluctant to offer the whole of what he sees in his visions.
In Hellenistic and Roman times Tiresias' sex-change was embroidered upon and expanded into seven episodes, with appropriate amours in each, probably written by the Alexandrian Ptolemaeus Chennus, but attributed by Eustathius to Sostratus. Tiresias is presented as a complexly liminal figure, with a foot in each of many oppositions, mediating between the gods and mankind, male and female, blind and seeing, present and future, and this world and the Underworld.