It is said that it was on Buddha Poornima, the full moon night in Vaisakha (according to the Hindu calendar that usually falls in April or May), Lord Buddha was born. He was the founder of the Buddhist religion and is said to be the ninth avatar of Vishnu. It was on Buddha Poornima that he attained enlightenment and ultimately after preaching the five principles of life and the path of eight-fold truth for long, he attained 'Nirvana' or left the mortal world on this day itself