Wat Pho is one of Bangkok's oldest temples. It existed before Bangkok was established as the capital by King Rama I. It was originally named Wat Photaram or Podharam, from which the name Wat Pho is derived.[4][9] The name refers the monastery of the Bodhi tree in Bodh Gaya, India where Buddha is believed to have attained enlightenment.[6][10] The older temple is thought to have been built or expanded some time in the reign of King Phetracha (1688–1703) of the Ayuthaya period on an even earlier temple site, but its founder is unknown.[6][11] After the fall of Ayutthaya to the Burmese, King Taksin moved the capital to Thonburi where he located his palace beside Wat Arun on the opposite side of the river from Wat Pho, and the proximity of Wat Pho to this royal palace elevated it to the status of a wat luang (royal monastery).[6]
In 1782, King Rama I moved the capital from Thonburi across the river to Bangkok and built the Grand Palace adjacent to Wat Pho. In 1788, he ordered the construction and renovation at the old temple site of Wat Pho, which had by then become dilapidated.[1] The site, which was marshy and uneven, was drained and filled in before construction began. During its construction Rama I also initiated a project to remove Buddha images from abandoned temples in Ayutthaya, Sukhothai, as well other sites in Thailand, and many of these Buddha images were kept at Wat Pho.[12] These include the remnants of an enormous Buddha image from Ayuthaya's Wat Phra Si Sanphet destroyed by the Burmese in 1767, and these were incorporated into a chedi in the complex.[13] The rebuilding took over seven years to complete, and 12 years after work began, in 1801, the new temple complex was renamed Phra Chetuphon Vimolmangklavas in reference to the vihara of Jetavana, and became the main temple for Rama I.[14][15]