This is a large historic temple complex located to the southeast of Si Satchanalai town. The decorative stucco bearing the Bayon art style of ancient Khmer found at the main entrance of the temple as well as archaeological evidence excavated here; including foundations of earlier brick structures found beneath 2 buildings called Wiharn (vihara) Luang and Wiharn Phra Song Phi Nong and fragments of roofing tile with designs in Bayon art style, point out clearly that Wat Phra Si Ratanamahathat was originally founded before Sukhothai kingdom. Some scholars suggest that it was firstly constructed during the times of Pho Khun Si Nao Nam Thum, or around the early 13th century AD. Important buildings of this temple that can be seen in the present are as follows.