Vesak, also known as Buddha Jayanti or Buddha Purnima is the most sacred day in the Buddhist calendar. It is the most important festival of the Buddhists and is celebrated with great enthusiasm. The exact date of Vesak is the first full moon in the fourth month in the Chinese lunar calendar. The date varies from year to year in the Gregorian calendar but is typically in May.
Followers of Buddhism have been celebrating Buddhist festivals for centuries, but the decision to celebrate this day formally was only taken at the first conference of the World Fellowship of Buddhists held in Sri Lanka in 1950. Although Buddhists regard every full moon as sacred, the moon of the month of Vaisakh has special significance because on this day the Buddha was born, attained enlightenment (nirvana), and attained parinirvana (nirvana-after-death of the body) when he died.