In Sri Lanka, there is a significant and deeply moon-related festival — the Full Moon Poya Day. Every month, on the day of the full moon according to the lunar calendar, Sri Lankans celebrate this sacred occasion. With twelve full moons in a year, there are twelve Poya Days in total. Each one is closely connected to the life of the Buddha and carries its own unique spiritual significance.
Among them, the Poson Full Moon Poya Day in June commemorates the introduction of Buddhism to Sri Lanka. In terms of scale and significance, it is second only to Vesak among the twelve Full Moon Poya Days.
According to historical records, in the 3rd century BCE, after Emperor Ashoka of India’s Maurya Dynasty unified the Indian subcontinent, he converted to Buddhism and began actively spreading the Dharma to neighboring regions. His son, Mahinda, was sent as a missionary to Sri Lanka.
At that time, King Devanampiya Tissa of Sri Lanka encountered Mahinda while hunting on Mihintale Mountain. Through a series of insightful questions and answers, Mahinda tested the king’s intelligence and wisdom. Satisfied with his responses, Mahinda began to preach the teachings of the Buddha. Deeply inspired, King Devanampiya Tissa converted to Buddhism, becoming the first Buddhist monarch in Sri Lankan history.
Mahinda was then welcomed into the capital city of Anuradhapura to continue spreading Buddhism. Later, his sister Sanghamitta also arrived in Sri Lanka to establish the order of Buddhist nuns and further promote the faith.
With the enthusiastic support of the royal family, Buddhism quickly spread and took root in Sri Lanka, exerting a profound influence on the nation’s politics, culture, and society ever since.
As a result, the Poson Full Moon Poya Day became one of the most important Buddhist festivals in Sri Lanka. Each year, grand celebrations are held across the country, especially at Mihintale — the birthplace of Buddhism in Sri Lanka — and Anuradhapura, the ancient capital.
During the Poson Full Moon Poya Day, the sale of alcohol and meat is prohibited. Sri Lankans bathe and dress in clean clothes to show reverence and respect for the occasion, and many take part in almsgiving activities.
Devout Buddhists visit temples to make offerings, listen to sermons, and climb the 1,840 steps of Mihintale Mountain to worship at its many sacred Buddhist sites.
