Vesak (Sinhalese), Vesakha (Pali), Vaisakha (Sanskrit) is the name used for the 2nd month in Sri Lankan traditional Moon calendar (Lunar calendar) which corresponds with the month of May in the Gregorian calendar (Solar calendar).
It was on the full moon day in the month of Vesak, Prince Siddharta was born, became enlightened and attained Mahaparinibbāna. The full moon day of Vesak is celebrated by Buddhists honouring these three important occasions of the life of the Buddha.
The significance of Vesak lies with the Buddha’s teaching of cessation of suffering and universal peace to all humankind. It is a message to urge followers to do that which is good and to turn away from evil. It is a message of peace and perfect harmony between human beings and nature.
Vesak is associated with three important locations of Buddhist history – Lumbini in Nepal, the birth place of Prince Siddharta, Bodh Gaya (Buddha Gaya) Bihar State in India where The Buddha attained the most exalted Enlightenment under a Bodhi Tree and Kushinagar (Kusinara) in Uttar Pradesh, India where The Buddha attained Mahaparinibbana.
These three incidents in the life of Buddha is known in Sri Lanka as “Themagula” or the three Buddhist auspicious events – Birth, Enlightenment and Mahaparinibbana of The Buddha and celebrated in large scale in Sri Lanka and other Buddhist countries.
The United Nations General Assembly accepted the importance of “Vesak” and in 1999 by its resolution 54/115 acknowledged that Buddhism as one of the oldest religions in the world contributing to the spirituality of humanity for over two and half millennia and is commemorated annually at the United Nations Headquarters and UN Offices.