Tyro

Tyro was married to Cretheus (with whom she had one son, Aeson) 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 was born Pelias and Neleus, twin boys. Tyro exposed her sons on a mountain and they were raised by a maid. When they reached adulthood, Pelias and Neleus found Tyro and killed her stepmother, Sidero, for having mistreated her. Sidero hid in a temple to Hera but Pelias killed her anyway, causing Hera's undying hatred of Pelias.