Vatadageya is an ancient Stupa designed which is commonly known as a Stupa House. Polonnaruwa is home for two famous Vatadageya; one called the Medirigiriya Vatadageya and the other the Vatadageya which is situated in the Polonnaruwa Dalada Maluwa.
The Polonnaruwa Vatadageya is by far the best preserved Vatdageya in Sri Lanka as of today. This Vatadageya is believed to have been constructed during the reign of King Parakramabahu. However, King Nissanka Malla carried out a few renovations during his reign (1187-1196).
A well-preserved Sandakada Pahana (moonstones) that belongs to the Polonnaruwa age can be seen at the entrance of this vatadaheya. There are two Muragal (guard stones) on both sides of the door and a tiny staircase with a few steps followed. From the ground level to the center level outer circle, there is only one door. Upon entering from this northern door, there are four doorways (situated facing north, east south and west) to reach the top level that is elevated from the center level.
A stupa is present which occupies middle stage and there are four seated Buddha statues situated in four directions. Although there is no longer the wooden roof, some reaming stone pillars can be seen. These pillars are arranged to support the roof in concentrated rows.
However the oldest Vatadagey is supposed to be at the Thuparama Temple in Anuradhapura. This was built by King Vasaba on an already existing Stupa. It is common knowledge that Vatadageyas as constructed enclosing stupas where enshrined relics of the Lord Buddha were placed. It is believed that the Polonnaruwa Vatadageya may at some point in time have carried the sacred tooth relic of the Lord Buddha.
It is very evident that Kings of centuries ago were very pious in that they always saw to it that the sacred relics of the Lord Buddha were enshrined in proper places with much security ensured.