Mahishasura was a pious devotee to Brahma and was rewarded with a boon that no man or god would be able to conquer him. Thus invincible, he battled the gods and took over the heavens. Helpless against Brahma's boon, the gods appealed to the goddess Parvati, who agreed to harness the shakti of all female celestial beings to fight Mahishasura. She assumed the form of Durga and each god offered her a weapon - Shiva gave his trident, Vishnu gave his chakra, and Vayu donated his bow and arrow. Durga created seven female warriors called matrikas to assist in her task and after nine days of fighting, she vanquished Mahishasura and his army and restored the heavens to the gods.