Sri Lanka is the oldest continually Buddhist country, Theravada Buddhism being the major religion in the island since its official introduction in the 2nd century BC by Venerable Mahinda, the son of the Emperor Ashoka of India during the reign of King Devanampiya- Tissa.

Later, the nun Sanghamitta, the daughter of Asoka, was said to have brought the southern branch of the original Bodhi tree, where it was planted at Anuradhapura. From that day up to the present, the Buddhists in Sri Lanka have paid and are paying the utmost reverence to this branch of the Bodhi Tree under the shade of which the Master achieved Enlightenment.

Monks from Sri Lanka have had an important role in spreading Buddhism throughout South-east Asia. It was in Sri Lanka, in the 1st century AD the Buddhist monks assembled in Aloka-Vihara and wrote down the Tripitaka, the three baskets of the Teachings, known as the Pali scriptures for the first time.  It was Sri Lankan nuns who introduced the Sangha of nuns into China in 433AD