Mahākassapa Thera was a 12th-century Sri Lankan forest monk and an abbot of Dimbulagala Raja Maha Vihara, a forest monastery outside of Polonnaruwa. [1] Mahākassapa who was well versed in Vinaya, presided over the Buddhist council convened by King Parakramabahu I (1153-1186) whose main goal was to reorganize, reform and unify the Sangha. [2] An inscription at Gal Vihara states that with Mahākassapa's advice, the council expelled hundreds of corrupt monks and unified the Sangha under one single monastic Nikaya, the Mahavihara sect. [3] Mahākassapa also wrote several works on Vinaya.