Tiresias was a blind prophet of Apollo in Thebes. I use they/them pronouns for Tiresias as a personal choice due to the complexities surrounding their gender/sex, but most sources use he/him.
There are many myths and stories surrounding Tiresias, throughout Greek, Hellenistic, and Roman mythology. In Greek mythology, the story goes that Tiresias was transformed into a woman by Hera as 'punishment' for hitting a pair of copulating snakes with their stick. Tiresias remained as a woman for seven years following, and lived a full life during that time; they became a priestess of Hera, married, and had children.
In Hellenistic and Roman mythology, the story of Tiresias's sex-change was expanded upon. Tiresias was often presented as a "complexly liminal figure", constantly 'between': between humankind and the gods, male and female, blind and seeing, present and future, this world and the Underworld, etc. They were also changed between woman and man several times by several gods.
Tiresias has been referenced as one of the earliest transgender figures in dramatic literature. There are multiple pieces of media that use them and their stories as a reference point for telling stories of modern transgender people, such as "The Cinema Show", a song by the British progressive rock band Genesis (1973): "I have crossed between the poles, for me there's no mystery. Once a man, like the sea I raged, once a woman, like the earth I gave". There is also a French film, "Tiresia" (2013), that uses their story as a similar reference.
There are also several different myths that explain the relationship between their clairvoyance and their blindness. One such myth says that Athena blinded them after they saw her bathing nude. Tiresias's mother, a nymph of Athena, begged for her to reverse this. She couldn't do so, but "cleaned his ears" as repayment, which gave them the ability to understand birdsong, which was one explanation for how they knew the future: by listening to the birds.
Another say that Zeus and Hera asked Tiresias to settle an argument about sexual pleasure. When Tiresias took Zeus's side (claiming women took more pleasure from sex than men), Hera cursed them with blindness out of rage. As repayment, Zeus gave Tiresias the gift of foresight and a lifespan of seven lives.