"Tantra-sastra is a distinct tradition in ancient Indian culture. Scholars hold that its origin goes back to prehistoric times. Its ancient form can be found in the Atarva Veda and Yajur Veda. There are statements in Vedic literature like “the letter a is all speech” (Aitareya Aranyaka 2,3,6) and “A is brahman”...which remind one of the concept of matrka, which came to be expanded in the tantra of the Saivas, Saktas, and Buddhists."