Most of the 8th-century Ratnaprasada or 'Jewel Palace' lies in ruins today, though it was originally seven storeys high with a graceful, tiered roof. The entrance is marked by a beautifully carved muragala (guardstone), which depicts the Cobra King holding a vase of abundance and a flowering branch, with a dwarf attendant at his feet and his head framed by a cobra hood.

The monks of Ratnaprasada monastery often gave sanctuary to people in trouble with the authorities, and this led to a major conflict with the king. When court officials at odds with the king took sanctuary in the Ratnaprasada, the king sent his supporters to capture and execute them. The monks, disgusted at this invasion of a sacred place, departed en masse. The general populace, equally disgusted, besieged the Ratnaprasada, captured and executed the king’s supporters and forced the king to apologise to the departed monks in order to bring the monks back to the city and restore peace.

To the south of the Ratnaprasada is the Lankarama, a 1st-century-BC dagoba.