Nergal
The most tenuous early myth behind Sagittarius is that of Nergal, the Sumerian and Babylonian god of the underworld. In this myth, Nergal, the god of war and plagues, refused to bow before the representative of Ereshkigal, the goddess of the underworld. Ereshkigal intended to kill him for his insult; however, the god Ea gave Nergal demons to defend himself and a wooden throne, possibly as a gift to appease the goddess. Nergal descended to the underworld with these items, but instead of following Ea's advice not to accept any hospitality Ereshkigal may offer, he became infatuated with and married her, becoming the god of the underworld. Some scholars believe that he was the first inspiration for Sagittarius; however, others disagree, since Nergal was not necessarily considered an archer.
Enkido
Later Mediterranean cultures interpreted the constellation as Enkido, a character in the Epic of Gilgamesh. According to this legend, Gilgamesh was a tyrant, who ruled over the city of Uruk. When the cries of his oppressed people reached the ears of the gods, they created a wild man, named Enkido, to challenge him. However, after wrestling with each other, they earned each other's respect and became best friends. Enkido's friendship softened Gilgamesh, who afterward became a gentle and just ruler. The Mesopotamians identified Gilgamesh with the modern constellation Orion and Enkido with Sagittarius.
Crotus
The Greeks identified the constellation as Crotus, the son of the god Pan and Eupheme, the nurse of the muses. Crotus was a satyr, a creature with the upper body of a human and the lower body of a goat. Although most satyrs were wild, uncultured and disrespectful, Crotus was gentle and became a great musician and hunter, who invented the bow. He grew up on Mount Helikon among the muses, who begged Zeus to place him among the stars as Sagittarius, the archer.
Chiron
A fourth myth often associated with Sagittarius is that of Chiron, the centaur. Like satyrs, centaurs were known for being wild and rude; however, Chiron was well known as a gentle teacher, a wise doctor and a skillful archer. He mentored many heroes, including Jason, Achilles and Hercules, who accidentally wounded him with a poisoned arrow. Being immortal, Chiron could not die; but he was in such agony, that he could not bear to live. Instead, he gave up his immortality and died in the place of Prometheus, whom the gods had sentenced to a slow death for giving mankind fire. Because of his goodness, the gods did not send him to Hades, but gave him a place among the stars. Some scholars believe that his constellation is actually Centaurus, but others identify it as Sagittarius.