The Shiva Purana describes that the creator god Brahma created all male beings, the Prajapatis, & told them to regenerate, which they were unable to do. Confronted with the resulting decline in the pace of creation, Brahma asked Shiva for help. To enlighten Brahma of his folly, Shiva appeared before him as Ardhanarishvara. Brahma prayed to the female half of Shiva to give him a female to continue creation. The goddess agreed & created various female powers from her body