In Greek mythology, Pēleús (Πηλεύς) was a hero who was already known to Homer. Peleus was the son of Aeacus, king of the island of Aegina, and Endeïs, the oread of Mount Pelion in Thessaly; he became the father of Achilles. He and his brother Telamon were friends of Heracles, serving in his expedition against the Amazons and his war against King Laomedon. Though there were no further kings in Aegina, the kings of Epirus claimed descent from Peleus.
Peleus and Telamon, his brother, killed their half-brother, Phocus, perhaps in a hunting accident, and fled Aegina to escape punishment. In Phthia, Peleus was purified by Eurytion and married Antigone, Eurytion's daughter. Peleus accidentally killed Eurytion during the hunt for the Calydonian Boar and fled from Phthia.
Peleus was purifed of the murder of Eurytion in Iolcus by Acastus. Astydameia, Acastus' wife, fell in love with Peleus but he scorned her. Bitter, she sent a messenger to Antigone to tell her that Peleus was to marry Acastus' daughter; Antigone hanged herself.
Astydameia then told Acastus that Peleus had tried to rape her. Acastus took Peleus on a hunting trip and hid his sword, then abandoned him right before a group of centaurs attacked. Chiron, the wise centaur, returned Peleus' sword and Peleus managed to escape. He pillaged Iolcus and dismembered Astydameia, then marched his army between the rendered limbs. After Antigone's death, Peleus married the sea-nymph Thetis and fathered Achilles by her. As a wedding present, Poseidon gave Peleus two immortal horses: Balius and Xanthus. Their wedding feast, however, was also the beginning of the quarrel that led to the Judgement of Paris and eventually to the Trojan War.
Thetis attempted to render her son Achilles invulnerable. In a familiar version, she dipped him in the River Styx, holding him by one heel, which remained vulnerable. In an early and less popular version of the story, Thetis anointed the boy in ambrosia and put him on top of a fire to burn away the mortal parts of his body. She was interrupted by Peleus and she abandoned both father and son in a rage, leaving his heel vulnerable (a nearly identical story is told by Plutarch, in his On Isis and Osiris, of the goddess Isis burning away the mortality of Prince Maneros of Byblos, son of Queen Astarte, and being likewise interrupted before completing the process). Peleus gave him to Chiron, on Mt. Pelion (which took its name from Peleus), to raise.