Wat Phra Sri Sanphet (Thai: วัดพระศรีสรรเพชญ์) is situated on the City Island in Ayutthaya’s World Heritage Park in Pratuchai sub-district. It has been registered as a national historic site by the Fine Arts Department since 5 March 1935. This monastery was the most important temple of Ayutthaya and situated within the Royal Palace grounds. It served as a model for the Temple of the Emerald Buddha in Bangkok.
In 1350, Prince U-Thong ordered a palace built in an area called Nong Sano, actual the area in the vicinity of Bueng Phra Ram. The palace contained three wooden buildings named "Phaithun Maha Prasat", "Phaichayon Maha Prasat", and "Aisawan Maha Prasat". Upon finalization of the palace in 1351, he established Ayutthaya as his capital and was bestowed the title of King Ramathibodi I. The original size of the old palace compound is believed to be the same as the area of Wat Phra Sri Sanphet today.
Wat Phra Sri Sanphet, being part of the royal palace, was exclusively used by the Ayutthayan Kings. No clergy was allowed to reside on the grounds, with exception of an occasionally invitation to pray and to perform ceremonies such as the taking of an oath of allegiance for royal officers and for preaching and merit-making by the King. The expansion of the temple caused the moving of the Buddhist center from Wat Mahathat to Wat Phra Sri Sanphet.
During his reign King Rama I (1782 -1809 A.D.) of the Ratanakosin Period ordered the transfer of the inner core of Phra Buddha Chao Sri Sanphet from Ayutthaya to Wat Phra Chetuphon in Bangkok, and had it placed in a chedi specially built for the purpose. Another Buddha image of importance called Phra Buddha Lokanat was also brought to this wat at about the same time.