about half of all monks encountered by Xuanzang in 7th-century India were Mahayanists. Early Mahayana schools of thought included the Mādhyamaka, Yogācāra, and Buddha-nature (Tathāgatagarbha) teachings. Mahayana is today the dominant form of Buddhism in East Asia and Tibet. Several scholars have suggested that the Prajñāpāramitā sūtras, which are among the earliest Mahāyāna sūtras, developed among the Mahāsāṃghika along the Kṛṣṇa River in the Āndhra region of South India. The earliest Mahāyāna sūtras to include the very first versions of the Prajñāpāramitā genre, along with texts concerning Akṣobhya Buddha, which were probably written down in the 1st century BCE in the south of India. A.K. Warder believes that "the Mahāyāna originated in the south of India and almost certainly in the Āndhra country." Anthony Barber and Sree Padma also trace Mahayana Buddhism to ancient Buddhist sites in the lower Kṛṣṇa Valley, including Amaravati Stupa, Nāgārjunakoṇḍā and Jaggayyapeṭa. Shunga dynasty (2nd–1st century BCE) The Shunga dynasty (185–73 BCE) was established about 50 years after Ashoka's death. After assassinating King Brhadrata (last of the Mauryan rulers), military commander-in-chief Pushyamitra Shunga took the throne. Buddhist religious scriptures such as the Aśokāvadāna allege that Pushyamitra (an orthodox Brahmin) was hostile towards Buddhists and persecuted the Buddhist faith. Buddhists wrote that he "destroyed hundreds of monasteries and killed hundreds of thousands of innocent Monks": 840,000 Buddhist stupas which had been built by Ashoka were destroyed, and 100 gold coins were offered for the head of each Buddhist monk. Modern historians, however, dispute this view in the light of literary and archaeological evidence. They opine that following Ashoka's sponsorship of Buddhism, it is possible that Buddhist institutions fell on harder times under the Shungas, but no evidence of active persecution has been noted. Etienne Lamotte observes: "To judge from the documents, Pushyamitra must be acquitted through lack of proof." Another eminent historian, Romila Thapar points to archaeological evidence that "suggests the contrary" to the claim that "Pushyamitra was a fanatical anti-Buddhist" and that he "never actually destroyed 840,000 stupas as claimed by Buddhist works, if any". Thapar stresses that Buddhist accounts are probably hyperbolic renditions of Pushyamitra's attack of the Mauryas, and merely reflect the desperate frustration of the Buddhist religious figures in the face of the possibly irreversible decline in the importance of their religion under the Shungas. During the period, Buddhist monks deserted the Ganges valley, following either the northern road (uttarapatha) or the