The west pediment depicts the battle of the Centaurs against the Lapiths. The centaurs were decendants of Ixion, who made love to a cloud (created by Zeus) which resembled Hera. The offspring were half-man, half-horse. One day, King Peirithous of the Lapiths invited the centaurs to the wedding of his daughter Deidameia. During the feast and drinking, the centaurs got riotous and attempted to abduct the bride and the women of the Lapiths. Peirithous, Theseus, and the Lapiths leaped to their rescue and defeated the centaurs. The pediment shows the battle at the height of its fury.

In the center stands stern Apollo, watching over the battle. On either side of him are Theseus and Peirithous, about to slay the centaurs. Various other figures of centaurs abducting women or battling Lapiths stretch out on either side, showing expressions of pain, determination, and desperation as hooves kick, hands strike, mouths bite, and nails scratch.
Centaur and Lapith Centaur and Woman
Apollo Central Group Theseus