Pirithoüs or Peirithoüs (both: pīrĬth´ōəs), in Greek mythology, king of the Lapithae. He and Theseus swore an oath of eternal friendship. Together they went on the Calydonian hunt and invaded the land of the Amazons. In a later exploit they attempted to abduct Persephone from Hades, where they were tricked into sitting on a magic bench from which they were unable to rise. After four years of torture Hercules descended to Hades and pulled Theseus from the bench, but when he reached for Pirithoüs the ground trembled and Pirithoüs was left behind. In some accounts Pirithoüs also escaped.