Her father, Salmoneus, was the brother of Athamas and Sisyphus. Tyro was married to Cretheus (also her uncle whom she had three sons, Aeson, Amythaon, Pheres) but she 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 was 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 (Salmoneus married Sidero when Alcidice, his wife and the mother of Tyro, died). 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, her paternal uncle and had two children. It was said that their children would kill Salmoneus, so Tyro killed them in order to save her father.
^Homer, Odyssey 11. 236–7, but Hesiod, Ehoiai fr. 30 (Merkelbach-West) says she fought with Salmoneus and was rescued by Zeus and led to the house of Cretheus, where she was raised. Pseudo-Apollodorus, Bibliotheca 1.9.8 confirms this.
^Pseudo-Apollodorus, Bibliotheca 1.9.8 adds that Pelias refused thereafter to honor Hera