In Greek mythology, Chiron or Cheiron ("hand" was held as the superlative centaur among his brethren. Like the satyrs, centaurs were notorious for being overly indulgent drinkers and carousers, given to violence when intoxicated, and generally uncultured. Chiron, by contrast, was intelligent, civilized and kind. He was known for his knowledge and skill with medicine. Sired by Cronus when he had taken the form of a horse and impregnated the nymph, Philyra, Chiron came from a different lineage than other centaurs, who were born of sun and raincloud, rendered by Greeks of the Classic period as from the union of the king Ixion, consigned to a fiery wheel, and Nephele ("cloud"), whom in the Olympian telling Zeus invented, to look like Hera.
Chiron married the nymph Chariclo who bore him three daughters, Hippe (Melanippe or Euippe), Endeis, and Ocyrhoe, and one son Carystus. Chiron, his wife and children lived on Mount Pelion.
A great healer, astrologer, and respected oracle, the last remaining centaur was most revered as a teacher and tutor.
His nobility is further reflected in the story of his death as Chiron sacrificed his life, allowing humanity to obtain the use of fire. Being the son of Kronos, a titan, he was immortal and so could not die. So it was left to Heracles to arrange a bargain with Zeus to exchange Chiron's immortality for the life of Prometheus who had been chained to a rock and left to die for his transgressions. Chiron had been poisoned with an arrow belonging to Heracles that had been treated with the blood of the Hydra. (In other versions, poison Chiron had given to the hero when he had been under the honorable centaur’s tutelage.) This had taken place during the visit of Heracles to the cave of Pholus on Mount Pelion in Thessaly when he visited his friend during his fourth labour in defeating the Erymanthian Boar. While they were at supper, Heracles asked for some wine to accompany his meal. Pholus, who ate his food raw, was taken aback. He had been given a vessel of sacred wine by Dionysus sometime earlier, to be kept in trust for the rest of the centaurs until the right time for its opening. At Heracles's prompting, Pholus was forced to produce the vessel of sacred wine. The hero, gasping for wine, grabbed it from him and forced it open. Thereupon the vapours of the sacred wine wafted out of the cave and intoxicated the wild centaurs, led by Nessus, who had gathered outside. They attacked the cave with stones and fir trees. Heracles was forced to shoot many arrows (poisoned, of course, with the blood of the Hydra) to drive them back. During this assault, Chiron was hit in the thigh by one of the poisoned arrows. After the centaurs had fled, Pholus emerged from the cave to observe the destruction. Being of a philosophical frame of mind, he pulled one of the arrows from the body of a dead centaur and wondered how such a little thing as an arrow could have caused so much death and destruction. In that instant, he let slip the arrow from his hand and it dropped and hit him in the foot, killing him instantly.
Ironically, Chiron, the master of the healing arts, could not heal himself, so he willingly gave up his immortality. He was honoured with a place in the sky, for the Greeks as the constellation Sagittarius, and in modern times represented by the constellation of the southern hemisphere, Centaurus.
Chiron saved the life of Peleus when Acastus tried to kill him by taking his sword and leaving him out in the woods to be slaughtered by the centaurs. Chiron retrieved the sword for Peleus. Some sources speculate that Chiron was originally a Thessalian god, later subsumed into the Greek pantheon as a centaur.
This is an excerpt from Wikipedia.