In Greek mythology, Achilles (Ancient Greek: ) was a Greek hero of the Trojan War, the central character and the greatest warrior of Homer's Iliad.

Achilles also has the attributes of being the most handsome of the heroes assembled against Troy.

Later legends (beginning with a poem by Statius in the first century AD) state that Achilles was invulnerable in all of his body except for his heel. Legend states that Achilles was semi-immortal, however his heel was vulnerable. Since he died due to a poisoned arrow shot into his heel, the "Achilles' heel" has come to mean a person's principal weakness.

Birth

Achilles was the son of the nymph Thetis and Peleus, the king of the Myrmidons. Zeus and Poseidon had been rivals for the hand of Thetis until Prometheus, the fire-bringer, warned Zeus of a prophecy that Thetis would bear a son greater than his father. For this reason, the two gods withdrew their pursuit, and had her wed Peleus.

As with most mythology there is a tale which offers an alternative version of these events: in Argonautica (iv.760) Hera alludes to Thetis's chaste resistance to the advances of Zeus, that Thetis was so loyal to Hera's marriage bond that she coolly rejected him.

However none of the sources before Statius makes any reference to this general invulnerability. To the contrary, in the Iliad Homer mentions Achilles being wounded: in Book 21 the Paeonian hero Asteropaeus, son of Pelagon, challenged Achilles by the river Scamander. He cast two spears at once, one grazed Achilles' elbow, "drawing a spurt of blood."

Also in the fragmentary poems of the Epic Cycle in which we can find description of the hero's death, Kúpria (unknown author), Aithiopis by Arctinus of Miletus, Ilias Mikrá by Lesche of Mytilene, Iliou pérsis by Arctinus of Miletus, there is no trace of any reference to his general invulnerability or his famous weakness (heel); in the later vase-paintings presenting Achilles' death, the arrow (or in many cases, arrows) hit his body.

Peleus entrusted Achilles to Chiron the Centaur, on Mt. Pelion, to be raised.

Achilles in the Trojan War

The first two lines of the Iliad read:

Sing, Goddess, of the rage, of Peleus' son Achilles

the accursed rage, which brought pain to thousands of the Achaeans.

Achilles is the only mortal to experience consuming rage. His anger is at some times wavering, but at other times he cannot be cooled. The humanization of Achilles by the events of the war is an important theme of the narrative.