The Visuddhimagga (Pali; English The Path of Purification), is the 'great treatise' on Theravada Buddhist doctrine written by Buddhaghosa approximately in 430 CE in Sri Lanka. It is a comprehensive manual condensing and systematizing the theoretical and practical teachings of the Buddha as they were understood by the elders of the Mahavihara Monastery in Anuradhapura, Sri Lanka. It sets out detailed practical instructions for developing purification of mind. This guide describes the methods of purification and the subjects of concentration..