Centaurs are treated in Greek sources as a people, a half-horse tribe of the Thessalian mountains, rather than as a symbol. Their defining episode is the Centauromachy: invited to the wedding of the Lapith king Pirithous, they grow drunk and seize the women, and the ensuing battle of order against animal appetite was carved on the Parthenon metopes and the temple of Zeus at Olympia as an emblem of civilisation over savagery.
Against this collective wildness stands one deliberate exception: Chiron, wise, just and immortal, tutor of Achilles, Jason and Asclepius, who is accidentally wounded by one of Heracles's poisoned arrows and, unable to die of it, surrenders his immortality and is set in the sky as Sagittarius (or, in some accounts, Centaurus). The contrast between the drunken many and the learned one is the whole point of the type: the centaur figures the human problem of reason yoked to animal nature, resolved in Chiron and lost in the rest.