Phegeus was a Greek mythological king who offered succor and his daughter, Arsinoe (named Alphesiboea in some versions), to Alcmaeon, who was fleeing from the Erinyes. Alcmaeon left his mother's, Eriphyle's, jewelry and clothing with him and then returned for it later in order to please the river god Achelous and have his daughter, Callirhoe, in marriage. Phegeus had his sons Agenor and Pronous kill Alcmaeon.