Proteus was the son of King Abas of Argos. He ruled Argos alongside Acrisius, his brother. However, Acrisius eventually exiled him. He fled to Lycia, where he married the daughter of King Iobates, and returned to Greece with an army. Acrisius gave him half the kingdom. Proteus then ruled Mycenae, succeeded by his son Megapenthes. He was approached by Bellerophon of Corinth to purify him of a murder. Proteus sent him to his father-in-law with a note, telling him to kill the messenger. Iobates sent him to kill the Chimaera.