Only a short stroll north of the royal palace ruins, the area known as the quadrangle is literally that - a compact group of fascinating ruins in a raised-up area bounded by a wall. It's the most concentrated collection of buildings you'll find in the ancient cities. As well as the following ruins, there's a recumbent image house, chapter house, Bodhisattva shrine and bodhi tree shrine.

In the southeast of the quadrangle, the vatadage is typical of its kind. Its outermost terrace is 18m in diameter and the second terrace has four entrances flanked by particularly fine guardstones. The moonstone at the northern entrance is reckoned to be the finest in Polonnaruwa, although not of the same standard as some of the best at Anuradhapura. The four entrances lead to the central dagoba with its four seated Buddhas. The stone screen is thought to be a later addition to the vatadage, probably by Nissanka Malla.

At the southern end of the quadrangle, the Thuparama Gedige is the smallest gedige (hollow Buddhist temple with thick walls) in Polonnaruwa, but is also one of the best - and the only one with its roof intact. The building shows a strong Hindu influence and is thought to date from the reign of Parakramabahu I. There are several Buddha images in the inner chamber, but they're barely visible in the late afternoon light.

The Gal Pota (Stone Book), immediately east of the vatadage, is a colossal stone representation of an ola book. It measures nearly 9m long by 1.5m wide, and is from 40cm to 66cm thick. The inscription on it, the longest such stone inscription in Sri Lanka (and there are many!), indicates that it was a Nissanka Malla publication. Much of it extols his virtues as a king, but it also includes the footnote that the slab, weighing 25 tonnes, was dragged from Mihintale, nearly 100km away!

Also erected by Nissanka Malla, the Hatadage is a tooth-relic chamber; it is said to have been built in 60 days.

The busy Nissanka Malla was also responsible for the Latha-Mandapaya. This unique structure consists of a latticed stone fence - a curious imitation of a wooden fence with posts and railings - surrounding a very small dagoba. The dagoba is encircled by stone pillars shaped like lotus stalks, topped by unopened buds. It is said that Nissanka Malla sat within this enclosure to listen to chanted Buddhist texts.

Nearly nothing is known about the ziggurat-style Satmahal Prasada, which may have been influenced by similar Mon-built stupas in Lamphun and Chiang Mai, Thailand. The construction consists of six diminishing storeys (there used to be seven), shaped like a stepped pyramid.

A shrine for the tooth relic, the Atadage is the only surviving structure in Polonnaruwa dating from the reign of Vijayabahu I.