Buddhism is practiced by 70.2% of the Sri Lankan's population with most being predominantly from Theravada school of thought. Most Buddhists are of the Sinhalese ethnic group with minority Tamils. Buddhism was introduced to Sri Lanka in the 2nd century BCE by venerable Mahinda Maurya. A sapling of the Bodhi Tree under which the Buddha attained enlightenment was brought to Sri Lanka during the same time. The Pāli Canon (''Thripitakaya''), having previously been preserved as an oral tradition, was first committed to writing in Sri Lanka around 30 BCE. Sri Lanka has the longest continuous history of Buddhism of any predominantly Buddhist nation. During periods of decline, the Sri Lankan monastic lineage was revived through contact with Thailand and Burma.