In the Jaffna Peninsula, on the island of Nainativu is situated the Nagadipa Vihara, one of the 16 sacred places of worship in Sri Lanka. According to the chronicles, in the 5th year after enlightenment, Lord Buddha visited Nagadipa to settle a dispute between two Nàga Kings - Chulodara and Mahodara regarding a gem throne.
The Bak Full Moon Poya commemorates Buddha's visit to Nagadipa to settle a dispute between Chulodara and Mahodara, two kings belonging to the Naga tribe, over the possession of a gem studded throne. It was a battle between uncle and nephew - the uncle being Mahodara and Chulodara, the nephew. Mahodara's sister had married another Naga king and Chulodara was their son. After the death of Chulodara's grandfather the gem studded throne which belonged to him was given to the daughter, Chulodara's mother.
Mahodara wanted to take possession of it. When Buddha came over from Jetavanarama in the city of Sravasti, He was accompanied by God Sumana , a protective deity residing on a tree at the entrance to the Vihara.The Buddha preached the virtues od non-violence to the two kings and urged them to be united. This plainting by Solius Mendis is at the Kelaniya Temple
According to legend, he was a resident of Nagadipa in his previous birth and had provided some Pacceka Buddhas with leaves from a tree to clean their alms bowls. The merit he acquired from that deed had made him a deity.
The Buddha preached the virtues of non-violence to the warring factions. He urged them to forget hating each other and be united. The two kings surrounded by their followers listened patiently to the Buddha and decided to end their enmity.
After the two warring kings made peace the throne was offered to the Buddha, who returned it to the Naga kings. It was later enshrined in the Nagadipa Stupa and soon became a place of Buddhist veneration.
There have been instances when Nagadipa and Ruhuna which were at times ruled by members of the royal family, were at other times administered by 'amatyas' or courtiers.
Nagadipa later came to be referred to as Nainativu island. Until the escalation of the northern war, Nagadipa was a popular place of worship with Buddhists from all over the island visiting the sacred place to venerate the spot hallowed by the Buddha.