As a follower of Artemis, Callisto, was the daughter of Lycaon, king of Arcadia, took a vow to remain a virgin, as did all the nymphs of Artemis. But to have her, Zeus disguised himself, as Artemis/Diana herself, in order to lure her into his embrace and rape her. Callisto was then turned into a bear, and gave birth to a chaild called Arcas, who later killed her in fear when she came to see him.