The centaurs of Greek mythology have been reinvented to a large extent by the workings of JK Rowling within the Harry Potter books. There is though a lot of similarities between the new versions of the centaur and those from Greek mythology. Centaurs were said to be drunkards and violent, imagery which can be seen by the majority within the Forbidden Forest. Just as JK Rowling had one centaur that stood out from the crowd though, with Firenze, Greek mythology had Chiron.
Chiron was by far the most cultured of all of the centaurs, perhaps representative of the fact that he was born from different parentage to the majority. Centaurs were said to have been born from King Ixion, king of the Lapiths, and the cloud nymph, Nephele. Chiron though was born after a relationship between Cronus, father of Zeus, and the oceanid nymph, Philyra. During the mating process though Cronus had transformed himself into a horse, and thus when Chrion was born, Philyra was so upset by how her new child looked that she rejected him.
Despite being rejected by his mother, Chiron grew up and became a wise and intelligent member of his race. Chiron was known in particular for his ability to tell the future, his astrological knowledge, and his knowledge of healing and medicine. It was a knowledge that Chrion was given to share with many of the most famous mortal heroes from Greek mythology, including the likes of Heracles, Jason, Theseus and Achilles. The tutorage of Achilles is perhaps the best known story, as Peleus put his son into the care of the centaur after Thetis had fled after trying to make Achilles immortal. Chrion had previously saved Peleus from being killed by the other centaurs, as well as helping him in his seduction of Thetis.
Chiron himself would tutor his students from his home on Mount Pelion, a little way apart form the other centaurs, although close to another of the wise centaurs, Pholus. His home also comprised of his wife, Chariclo, a nymph, and his four offspring, sisters Hippe, Ocyrhoe and Endeis, and a son Carystus.
Chiron was an immortal and yet in Greek mythology did die, although in his death he helped mankind. The location of Chiron's death was on Mount Pelion, but ironically the cause was one of his own students, Heracles. Heracles had just completed his fourth of his twelve tasks by defeating the Erymanthian Boar. Afterwards he had travelled to Mount Pelion to meet up with his friend, the other wise centaur, Pholus. As the pair ate Heracles asked for some wine to wash his food down, and thus Pholus brought forth a special wine as given to him by Dionysus. It was though a potent wine, and the fumes attracted the other centaurs to the cave. Driven with desire for the intoxicating liquor, the centaurs attacked Pholus' home, and to defend himself Heracles retaliated. This retaliation took the form of his bow and arrow, and with his arrows already having been dipped in the blood of the hydra, made for a lethal counterattack.
Many, if not all of the centaurs, were killed in the fighting. Chiron himself was attracted to Pholus' home by the commotion, and was accidentally struck by one of Heracles' arrows. Pholus was also killed by an arrow, although this was of his own doing, having examined it before letting it fall onto his hoof. The blood of the hydra did not kill Chiron, but caused him immense pain, and whilst he was unable to heal himself, he also could not die. Chiron asked for someway to relieve himself of the pain, so Chiron and Heracles came up with a plan. Heracles went to his father, Zeus, and offered Chiron's immortality in return for the release of the Titan Prometheus from his eternal punishment.
There is no real reason as to why Zeus would want Chiron's immortality, or why he would want to release Prometheus, other than the fact that it was being asked for by Heracles. Prometheus though was freed, and so was able to assist mankind, whilst Chiron was relieved of his pain, but continued his immortality as part of the Sagittarius constellation in the night sky.
As with many gods and creatures of Greek mythology, the name of Chiron seems to have been absorbed from previous Thessalian mythology. In Thessaly Chiron was a god of healing, and although he kept his powers he was put into a more subservient position with the rise of Hellenistic mythology.
The life of Chiron crossed over with the stories of many of the most famous Greek heroes, and even his death was seen as a side issue amongst the adventures of Heracles. Chiron though was the unlike of the Olympian gods as although classed as lesser being was both wise, kind and more human than the gods in residence on Mount Olympus.