In Greek mythology, Tyro was the daughter of Salmoneus and married Cretheus, but loved Enipeus. She gave birth to Pelias and Neleus, the twin sons of Poseidon. With Cretheus she had Aeson, Pheres, and Amythaon. Her father, Salmoneus, was the brother of Athamas and Sisyphus. Tyro was married to Cretheus but loved Enipeus, a river god. She pursued Enipeus, who refused her advances. One day, Poseidon, filled with lust for Tyro, disguised himself as Enipeus and from their union were born Pelias and Neleus, twin boys. Tyro exposed her sons on a mountain to die, but they were found by a herdsman who raised them as his own.
When they reached adulthood, Pelias and Neleus found Tyro and killed her stepmother, Sidero, for having mistreated their mother. Sidero hid in a temple to Hera but Pelias killed her anyway, causing Hera's undying hatred of Pelias – and her glorious patronage of Jason and the Argonauts in their long quest for the Golden Fleece. Pelias' half brother Aeson, the son of Tyro and Cretheus, was the father of Jason. Soon after, Tyro married Sisyphus and had two children. It was said that their children would kill Salmoneus, so Tyro killed them in order to save her father.