Tantricism delineates a broad religious movement which began in the first century AD and, at one time or another, became common throughout South Asia and even, primarily in the form of Tantric Buddhism, throughout East and Southeast Asia. tantra and Tantrika are sanskrit terms designating, respectively, a class of sacred texts and a follower of these texts, as contrasted with a follower of the vedas (vaidika). The origins of Tantricism are unknown, although the most likely places are northeast South Asia in present Bengal and Assam or northwest in the Swat Valley of Pakistan. The earliest Tantric texts are Buddhist, and include the Mahabhairochana Sutra (c 600 AD). Tantricism is an extension of ideas and practices already present in the Vedas, possibly in combination with some other indigenous or foreign religious influences. The movement expanded in and around modern Bengal during the Pala dynasty (8th -12th c AD), when many important texts of Tantric Buddhism were written.
The most distinctive doctrinal characteristic of Tantricism is the tendency to reject the duality of worldly existence (sangsara) and liberation (moksa/nirvana). Accordingly, Tantrics often deliberately flout the caste restrictions and ritual injunctions of Vedic and Brahmanical orthodoxy. This extends to the performance, in some Tantric groups, of prohibited sexual practices which symbolically represent the absence or extinction of duality through the union of male and female. Apart from these tendencies, Tantricism is primarily a set of ritual practices, including a strong component of magic, centred on the chanting of verbal formulas (mantraS) and also involving the use of gestures (mudra), diagrams (yantra, mandala) and sacrifices (homa, bali). [Robert A Yelle]