Poson full-moon poya day (Poson Poya Day, Poson Festival) is celebrated the arrival of Buddhism in Sri Lanka in the 3rd century BC, a festival of great historical and religious significance celebrated island-wide by Buddhists. Poson, held on the full moon day of June, commemorates the occasion over 2,000 years ago when Arahat Mahinda, son of Emperor Asoka of India, converted King Devanampiyatissa to Buddhism. The main center of celebration is Mihintale, the ancient monastic complex where the royal missionary monk Mahinda perched the first sermon to the ruling king and at Anuradhapura the ancient capital, to which large crowd of pilgrims converge. Mass religious observances, illuminations pageants are part of the celebrations.