Oedipus Rex, also known by its Greek title, Oedipus Tyrannus, or Oedipus the King, is an Athenian tragedy by Sophocles that was first performed around 429 BC. Originally, to the ancient Greeks, the title was simply Oedipus (Οἰδίπους), as it is referred to by Aristotle in the Poetics. It is thought to have been renamed Oedipus Tyrannus to distinguish it from Oedipus at Colonus, a later play by Sophocles. In antiquity, the term "tyrant" referred to a ruler with no legitimate claim to rule, but it did not necessarily have a negative connotation.

In Greek mythology, Tiresias was a blind prophet of Apollo in Thebes, famous for clairvoyance and for being transformed into a woman for seven years. He was the son of the shepherd Everes and the nymph Chariclo. Tiresias participated fully in seven generations in Thebes, beginning as advisor to Cadmus himself.