The Polonnaruwa Vatadage is an ancient structure dating back to the Kingdom of Polonnaruwa of Sri Lanka. It is believed to have been built during the reign of Parakramabahu I to hold the Relic of the tooth of the Buddha or during the reign of Nissanka Malla of Polonnaruwa to hold the alms bowl used by the Buddha. Both these venerated relics would have given the structure a great significance and importance at the time. Located within the ancient city of Polonnaruwa, it is the best preserved example of a vatadage in the country, and has been described as the "ultimate development" of this type of architecture. Abandoned for several centuries, excavation work at the Polonnaruwa Vatadage began in 1903.
Built for the protection of a small stupa, the structure has two stone platforms decorated with elaborate stone carvings. The lower platform is entered through a single entrance facing the north, while the second platform can be accessed through four doorways facing the four cardinal points. The upper platform, surrounded by a brick wall, contains the stupa. Four Buddha statues are seated around it, each facing one of the entrances. Three concentric rows of stone columns had also been positioned here, presumably to support a wooden roof. The entire structure is decorated with stone carvings. Some of the carvings at the Polonnaruwa Vatadage, such as its sandakada pahanas, are considered to be the best examples of such architectural features.
A unique feature of architecture of ancient Sri Lanka, vatadages were built for the protection of small stupas that had an important relic enshrined in them or were built on hallowed ground.If the Polonnaruwa Vatadage is the shrine built by Parakramabahu I, the relic of the tooth of the Buddha would have been enshrined within it. Another possibility is that the alms bowl used by the Buddha may have been enshrined here.Both these relics were important objects in ancient Sri Lankan culture, and would have made the Polonnaruwa Vatadage one of the most significant and venerated buildings in the country.
The Kingdom of Polonnaruwa ended in 1215 with an invasion from South India. The Polonnaruwa Vatadage appears to have been abandoned with the fall of the kingdom, and there is no mention of it in the chronicles in later periods. It was not until 1903 that the Department of Archaeology began excavation work at the site under Bell, who noted that it was "only a mound of earth" at the time.
The four Buddha statues, which depict the Dhyana mudra, are also carved from solid rock. Two of them are more or less intact today, while only parts of the other two remain. The stupa in the middle appears to have been of the Bubbulakara (bubble shaped) design commonly seen in Sri Lanka. The upper part has been destroyed, and only the dome shaped lower part now remains. However, it has only two Pesavas (the rings found at the base of stupas) rather than the traditional three. 
A vaṭadāge (Sinhala: වටදාගෙ) is a type of Buddhist structure found in Sri Lanka. It also known as a dage, thupagara and a cetiyagara. Although it may have had some Indian influence, it is a structure that is more or less unique to the architecture of ancient Sri Lanka. Vatadages were built around small stupas for their protection, which often enshrined a relic or were built on hallowed ground. Circular in shape, they were commonly built of stone and brick and adorned with elaborate stone carvings. Vatadages may have also had a wooden roof, supported by a number of stone columns arranged in several concentric rows.