Wat Phra Si Sanphet (Thai: วัดพระศรีสรรเพชญ์; "Temple of the Holy, Splendid Omniscient") was the holiest temple on the site of the old Royal Palace in Thailand's ancient capital of Ayutthaya until the city was completely destroyed by the Burmese in 1767. It was the grandest and most beautiful temple in the capital and it served as a model for Wat Phra Kaeo in Bangkok.
In 1350 U-thong, also known as King Ramathibodi I, ordered the construction of a royal palace in the same area that Wat Pra Si Sanphet stands today. The palace was completed in 1351 and King Ramathibodi established Ayutthaya as the capital of his Kingdom. 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. In 1448 King Borommatrailokanat built a new palace to the north and converted the old palace grounds to be a holy site. His son, King Ramathibodi II had two Stupa, which in Thailand are known as Chedis, built in 1492 where the ashes of his father, King Borom Trailokanath, and his brother, King Borommaracha III were buried.
In 1499 a viharn, or hall of worship, called “Vihara Luang” (Royal Chapel) was built on the palace grounds. King Ramathibodi II gave orders for a gigantic image of Buddha to be cast, and installed in Wat Si Sanphet. This image of Buddha was 16 meters high, covered in gold, and the pedestal was 8 meters in length. The core of the statue was made of bronze and weighed approximately 64 tons. The surface was covered with approximately 343 kilograms of gold. The statue took more than three years to complete. This statue, called “Phra Si Sanphetdayan”, was the main object of veneration within the royal chapel.