Shiva or Siva (shēˈvə) [key], one of the greatest gods of Hinduism, also called Mahadeva. The "horned god" and phallic worship of the Indus valley civilization may have been a prototype of Shiva worship or Shaivism. Shaivism is mentioned as early as the Upanishads and the Mahabharata (500–200 B.C.). Shiva is identified with the fierce Vedic god Rudra and, in his terrible aspect, is the god of destruction and cosmic dissolution. He is commonly worshiped in the form of the lingam, or symbolic phallus. His other main forms are the great yogi, or ascetic, and Nataraja, Lord of the Cosmic Dance. As a yogi he is depicted as seated deep in meditation in the Himalayas, holding a trident, a snake coiled around his neck, his body smeared with ashes, and his hair long and matted. As Nataraja, he is shown four-armed, bearing various emblems, and dancing on one foot on a prostrate demon. Shiva's mount is the bull Nandi, and his consort is the goddess Uma, Parvati, Durga, or Kali.