[[Image:Chiron.jpg|right|thumbnail|Chiron and Achilles
Chiron or Cheiron (Greek: KHEIRON ) was the eldest and wisest of the Centaurs, a tribe of half-horse men. But unlike the rest of this tribe he was an immortal god, a son of the Titan Kronos and so a half-brother of Zeus.
Chiron is the noblest specimen of a combination of the human and animal forms in the ancient works of art; for while the centaurs generally express the sensual and savage features of a man combined with the strength and swiftness of a horse, Chiron, who possesses the latter likewise, combines with it a mild wisdom. 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.
According to Apollodorus (i. 2. § 4), Chiron was born to the nymph Philyra, whose coupling with Kronos was interrupted by the sudden appearance of the Titan's wife. To escape her notice he transformed himself into a horse, and sired this half-equine son. Some sources speculate that Chiron was originally a Thessalian god, later subsumed into the Greek pantheon as a centaur.
Chiron had been instructed by Apollo and Artemis, and was renowned for his skill in hunting, medicine, music, gymnastics, and the art of prophecy. (Xen. Cyneg. 1; Philostr. Her. 9, Icon. ii. 2; Pind. Pyth. ix. 65.). Chiron was also a great teacher, and in his Pelian cave he mentored many great heroes including Jason, Peleus, Asklepios, Aristaios and Achilles.
Chiron married the nymph Chariclo who bore him three daughters, Hippe (Melanippe or Euippe), Endeis, and Ocyrhoe, and one son Carystus. His daughter Endeis was the mother of Peleus. (Apollod. iii. 12. § 6.) Chiron, his wife and children lived on Mount Pelion and, like the other centaurs, were expelled by the Lapithae; but sacrifices were offered to him there by the Magnesians until a very late period, and the family of the Cheironidae in that neighbourhood, who were distinguished for their knowledge of medicine, were regarded as his descendants.
- His friendship with Peleus, who was his grandson, is particularly celebrated. Cheiron saved him from the hands of the other centaurs, who were on the point of killing him, and he also restored to him the sword which Acastus had concealed. (Apollod. iii. 13. § 3, &c.) Cheiron further informed him in what manner he might gain possession of Thetis, who was doomed to marry a mortal.
- He is also connected with the story of the Argonauts, whom he received kindly when they came to his residence on their voyage, for many of the heroes were his friends and pupils. (Apollon. Rhod. i. 554; Orph. Argon. 375, &c.)
- 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 and was placed in the sky, for the Greeks as the constellation Sagittarius, and in modern times represented by the constellation of the southern hemisphere, Centaurus.
- Chiron has been adapted for fictional works, most notably in Dante's The Divine Comedy, in which he is the chief guardian of the seventh circle of Hell, and in Goethe's Faust (Part II, Act II, scene 5, the section titled "Lower Peneios"), where Faust seeks Chiron's aid in his search for Helen of Troy and receives important lessons in his search for complete understanding.
- John Updike's novel The Centaur is an expansion and interpretation of the story of Chiron, set in the context of 20th century small-town America. Chiron’s name, and the underlying mythology, serves to inform many of the root words connected with the ancient healing arts, e.g. cheiromancy, or the art of divining the will of the gods through the interpretation of the patterns of the hands.
- Chiron was written to be a close friend and mentor to the Amazon Wonder Woman in that DC Comics book.
- Chiron is also a sort of wavelength emitted by GUILT in Trauma Center: Under the Knife. The test is actually called "Chrial test"
- Chiron is a controllable unit in Age of Mythology – a mythology based real-time strategy computer game developed by Ensemble Studios and published by Microsoft Studios. Chiron is a Greek hero and is the equivalent of a cavalry archer. He is first encountered in the seventh episode of the campaign, "More Bandits" where he is being held captive. After being rescued Chiron accompanies Arkantos and Ajax on their adventures in Greece, Egypt and the underworld.