King Borom Rachathirat II (Chao Sam Phraya) built a temple on the site where his two elder brothers were cremated. His two brothers died in a power struggle to succeed their father, King Nakhon In who died in 1424. A series of bell-shaped chedis surround the main prang and a large oblong-shaped viharn is situated at the front. The architectural style evolved from the Khmer prasat, but has been adapted by the addition of a higher multi-layered base and an extended upper section. More corners were added to the main body and the tower section was extended to become corn-shaped. The antefixes, on the other hand, were attached to the body of the tower instead of leaving a decent gap between them which was common in Khmer prasats. These two temples are separated by Naresuan Road.
Admission fee for each site is 50 baht. A package ticket vilid for 30 days is also available at 220 baht each, covering admission to Wat phra Si Sanphet and the Ancient Palace Complex, Wat Mahathat, Wat Phra Ram, Wat Chai Watthanaram and Wat Maheyong .