Οχυγεν Occi Gen Octi Gen er at or Gene ξ Rator In Greek mythology , Peleus ( / ˈ p iː l i ə s , ˈ p iː lj uː s / ; Ancient Greek : Πηλεύς Pēleus ) was a hero, king of Phthia , husband of Thetis and the father of their son Achilles . This myth was already known to the hearers of Homer in the late 8th century BC. [ 2 ] In Greek mythology Phthia ( / ˈ θ aɪ ə / ; Ancient Greek : Φθία or Φθίη Phthía, Phthíē ) was a city or district in ancient Thessaly . [ 1 ] It is frequently mentioned in Homer 's Iliad as the home of the Myrmidons , the contingent led by Achilles in the Trojan War . It was founded by Aeacus , grandfather of Achilles, and was the home of Achilles' father Peleus , mother Thetis (a sea nymph ), and son Neoptolemus (wh...