century onwards. According to Flood, very little is known about who created the Tantras, nor much is known about the social status of these and medieval era Tantrikas. Flood states that the pioneers of Tantra may have been ascetics who lived at the cremation grounds, possibly from "above low-caste groups", and were probably non-Brahmanical and possibly part of an ancient tradition. By the early medieval times, their practices may have included the imitation of deities such as Kali and Bhairava, with offerings of non-vegetarian food, alcohol and sexual substances. According to this theory, these practitioners would have invited their deities to enter them, then reverted the role in order to control that deity and gain its power. These ascetics would have been supported by low castes living at the cremation places. Samuel states that transgressive and antinomian tantric practices developed in both Buddhist and Brahmanical (mainly Śaiva ascetics like the Kapalikas) contexts and that "Śaivas and Buddhists borrowed extensively from each other, with varying degrees of acknowledgement." According to Samuel, these deliberately transgressive practices included, "night time orgies in charnel grounds, involving the eating of human flesh, the use of ornaments, bowls and musical instruments made from human bones, sexual relations while seated on corpses, and the like." According to Samuel, another key element of in the development of tantra was "the gradual transformation of local and regional deity cults through which fierce male and, particularly, female deities came to take a leading role in the place of the yaksa deities." Samuel states that this took place between the fifth to eighth centuries CE. According to Samuel, there are two main scholarly opinions on these terrifying goddesses which became incorporated into Śaiva and Buddhist Tantra. The first view is that they originate out of a pan-Indian religious substrate that was not Vedic. Another opinion is to see these fierce goddesses as developing out of the Vedic religion. Alexis Sanderson has argued that tantric practices originally developed in a Śaiva milieu and was later adopted by Buddhists. He cites numerous elements that are found in the Śaiva Vidyapitha literature, including whole passages and lists of pithas, that seem to have been directly borrowed by Vajrayana texts. This has been criticized by Ronald M. Davidson however, due to the uncertain date of the Vidyapitha texts. Davidson argues that the pithas seem to have been neither uniquely Buddhist nor Śaiva, but frequented by