Construction of the Chedis of what is now named Wat Phra Si Sanphet, started probably during the reign of King Trailok .
The compound was actually located within the Royal Palace grounds. There were no residing monks, and the temple was used for royal ceremonies and for storing royal relics. The three chedis are believed to keep the ashes of three Kings : King Trailok, King Borom Ratchathirat III, and King Rama Thibodi II, as well as Buddha relics.