(Pāli). Literally ‘Great monastery’. For many centuries a monastery (vihāra) that was the main seat of the ancestral branch for present-day Theravāda Buddhism in Sri Lanka. It was founded by King Devānaṃpiya Tissa (247–207 bce) in his capital of Anurādhapura on the site of the Tissārama, given to visiting missionaries from Aśoka's court, and it included many buildings and shrines. Its residents, claiming to represent the orthodox tradition of Sri Lankan Buddhism, referred to themselves as the Theriya Nikāya (or Theravāda) in contrast to the monks of the rival monasteries of Abhayagiri.known as the Dhammaruci Nikāya and Jetavana (in fact all three schools laid claim to the name Theriya Nikāya or Theravāda while seeking to deny it to their opponents). Though they managed to live side by side without major conflicts for long periods, the fraternities of the Mahāvihāra and of the Abhayagiri had earlier come into conflict in a struggle for control of the Buddhist tradition in the island. When the Abhayagiri monks then openly adopted the heretical Vaitulya Piṭaka the animosity between the monks of the two establishments became very bitter and resulted in the heretical books being burnt and the destruction of the Mahāvihāra. The two communities remained separate until 1165 when a council was held at Anurādhapura and reconciliation was achieved. When Anurādhapura was abandoned around the 13th century, the history of the Mahāvihāra came to an end.