has always been the worship of Śiva, especially in the form representing him as half male, half female. This cult is not far from Śâktism and many allusions[318] in the Râjataranginî indicate that left-hand worship was known, though the author satirizes it as a corruption. He also several times mentions[319] Mâtri-cakras, that is circles sacred to the Mothers or tantric goddesses. In Nepal and Tibet tantric Buddhism is fully developed but these countries have received so much from India that they exhibit not a parallel growth, but late Indian Tantrism as imported ready-made from Bengal. It is here that we come nearest to the origins of Tantrism, for though the same beliefs may have flourished in Udyâna and Kashmir they did not spread much in the Panjab or Hindustan, where their progress was hindered at first by a healthy and vigorous Hinduism and subsequently by Mohammedan invasions. But from 700 to 1197 A.D. Bengal was remote alike from the main currents of Indian religion and from foreign raids: little Aryan thought or learning leavened the local superstitions which were infecting and stifling decadent Buddhism. Hsüan Chuang informs us that Bhaskaravarma king of Kâmarûpa[320] attended the fêtes celebrated by Harsha in 644 A.D. and inscriptions found at Tezpur indicate that kings with Hindu names reigned in Assam about 800 A.D. This is agreeable to the supposition that an amalgamation of Śivaism and aboriginal religion may have been in formation about 700 A.D. and have influenced Buddhism. In Bihar from the eighth century onwards the influence of Tantrism was powerful and disastrous. The best information about this epoch is still to be found in Târanâtha, in spite of his defects. He makes the interesting statement that in the reign of Gopâla who was a Buddhist, although his ministers were not (730-740 A.D.), the Buddhists wished their religious buildings to be kept separate from Hindu temples but that, in spite of protests, life-sized images of Hindu deities were erected in them.[321] The ritual too was affected, for we hear several times of burnt offerings[322] and how Bodhibhadra, one of the later professors of Vikramaśila, was learned in the mystic lore of both Buddhists and Brahmans. Nalanda and the other viharas continued to be seats of learning and not merely monasteries, and for some time there was a regular succession of teachers. Târanâtha gives us to understand that there were many students and authors but that sorcery occupied an increasingly important position. Of most teachers we are told that they saw some deity, such as Avalokita or Târâ. The deity was summoned by the rites already described[323] and the object of the performer was to obtain magical powers or siddhi. The successful sorcerer was known as siddha, and we hear of 84 mahâsiddhas, still celebrated in Tibet, who extend from Rahulabhadra Nâgârjuna to the thirteenth century. Many of them bear names which appear not to be Indian.