The zodiacal constellation Sagittarius represents the centaur Chiron. Most of the centaurs were regarded in myth as bestial--they were, after all, half horse. However, the ancient Greeks had a great deal of respect for the horse, and so were reluctant to make the centaurs entirely bad.
In fact, Chiron was renowned for his gentleness. He was an excellent archer, musician, and physician, and tutored the likes of Achilles, Jason, and Hercules.
Chiron, however, was accidentally shot and wounded by Hercules. The arrow, which had been dipped in the poison of the Lernaean Hydra, inflicted great suffering on Chiron--so great, in fact, that even the talented physician could not cure himself.
In agony, but as an immortal unable to find release in death, Chiron instead offered himself as a substitute for Prometheus. The gods had punished Prometheus for giving fire to man by chaining him to a rock. Each day an eagle would devour his liver, and each night it would grow back.
Jupiter, however, had at the request of Hercules agreed to release Prometheus if a suitable substitute could be found. Chiron gave up his immortality and went to Tartarus in place of Prometheus; in recognition of his goodness, Jupiter placed him in the stars.
From the northern hemisphere, Sagittarius may be seen only in the summer, lying low in the south. The Milky Way runs through Sagittarius. 背景故事：
在遥远古希腊的大草原中，驰骋着一批半人半兽的族群，这是一个生性凶猛的族群。“半人半兽”代表着理性与非理性、人性与兽性间的矛盾挣扎，这就是“人马族”。
人马族里唯独的一个例外——奇伦。奇伦虽也是人马族的一员，但生性善良，对待朋友尤以坦率著称，所以奇伦在族里十分受人尊敬，有一天，希腊最伟大的英雄海格力斯，来拜访他的朋友，这位幼年即用双手扼死巨蛇的超级大力士，一听说人马族也是一个擅长酿酒的民族，想到香醇的佳酿，也不管这酒是人马族的共有财产，便强迫他的朋友偷来给他享用，否则就打死他，所有人都知道，海格力斯是世间最强壮的人，连太阳神阿波罗都得让他三分，迫于无奈，这个人马族人只有照着它的意思办了。
正当海格力斯沉醉在酒的芬芳甘醇之际，酒的香气早已弥漫了整个部落，所有人马族都厉声斥责海格力斯，海格力斯怒气冲天，拿着他的神弓奋力追杀人马族，人马族们仓皇的逃至最受人尊敬的族人奇伦家中，这时奇伦在家中听见了屋外万蹄奔踏及惊慌的求救声，他连想都没想，开门直奔出去，说时迟那时快，海格力斯拉满弓瞬间射出去，竟然射中了奇伦的心脏，善良无辜的奇伦为朋友牺牲了自己的生命。
天神宙斯听见了人马的嘶喊，于是他双手托起奇伦的尸体，往天空一掷，奇伦瞬间幻化成数颗闪耀的星星，形体就如人马族，从此为了纪念奇伦，这个星座就称为“人马座”，也就是我们所说的“射手座”。
