According to the Mahavamsa, the ancient chronicle of the island, the Buddha who foresaw an imminent war between two Naga Kings, Chulodara and Mahodara, uncle and nephew, over a jewel-studded throne, made his second visit to the country. The Mahavamsa also records that the Buddha was accompanied by a deity on his journey. The story depicts the Buddha as a fine diplomat, as his arrival prevented a huge carnage. It is also believed that on a Bak Full Moon Poya day King Maniakkhita invited the Buddha to visit Kelaniya. The construction of the Nagadeepa Rajamaha Viharaya (temple) also commenced on a Bak Poya Day.
As the story goes the Buddha hovered in mid-air, above the battle field and brought darkness upon the land. Later he illuminated the whole area. When the Naga Community witnessed this miracle, they joyfully paid their obeisance. The Buddha then expounded Kakoluka, Phandana, Latuka, and Wattaka Jataka tales from the Pansiyapanas Jathakaya (Stories of the Buddha’s past lives), explaining the evils of discord and the value and the benefits that they could amass from being united and living in peaceful co-existence. Hence, the Buddha’s sermons to the Naga community contains a strong message of significance even today.
A great teacher and communicator, he followed the approach of storytelling to convince the audience. A deeper study of the Jataka stories narrated by the Buddha presents the themes of peace, character building and personality development. The primary lesson of Bak Full Moon Poya Day is that victory generates hatred and the vanquished live in misery; one whose mind is calm, tranquil and undisturbed lives happily.