In Greek mythology , the bravest and strongest of the Greek warriors in the Trojan War .
Because his mother dipped him into the River Styx , he was invulnerable except at the heel by which she held him. During the war against Troy Achilles took 12 nearby cities, but after a quarrel with Agamemnon he refused further service. He allowed his beloved cousin Patroclus to fight in his armor, and when Hector slew Patroclus, Achilles returned to battle, killed Hector, and dragged his body around the walls of Troy. Homer mentions Achilles' funeral but not the circumstances of his death; the later poet Arctinus relates that Paris killed Achilles with an arrow guided by Apollo .