Mnemosyne — Classical Greek Myth Library

Callisto was a companion of Artemis, sworn to virginity, and in Arcadian myth a daughter of Lycaon (or, in variant genealogies, of Nycteus or Ceteus). Zeus desired her. Disguising himself as Artemis (a widespread classical motif), or approaching her by other deceit, he lay with her. Callisto conceived Arcas, eponym of the Arcadians. When her pregnancy was discovered—often while bathing with Artemis—the goddess in anger transformed Callisto into a bear, or drove her from the band. In Apollodorus’s summary, Zeus turned Callisto into a bear to hide the affair from Hera; Hera then persuaded Artemis to shoot the bear as a wild beast. Zeus placed Callisto among the stars as the Great Bear (Ursa Major); Arcas was set nearby as Arctophylax / Boötes, or became the ancestral king of Arcadia after being saved and reared. Pausanias records Arcadian cult and tomb traditions of Callisto and links Arcas to the land’s naming. The story binds Artemis’s virgin huntress circle, Zeus’s adulteries, Hera’s revenge, and Arcadian ethnography to the bear constellation.