The city of Ayutthaya was founded by King Ramathibodi I in 1351,[a] though it is likely to be significantly older, based on evidence showing that the area was already populated during the Mon Dvaravati period.

[1][2] Additionally, Prince Damrong has also attested to the existence of a city named Ayodhya, founded by the Khmers ruling from Lopburi at the point where the three rivers meet.

[3] An excavation map shows traces of an ancient baray (water reservoir) close to the southwestern tip of Wat Yai Chai Mongkhon, which could have been built on a former important Khmer temple complex.

[6] In 1969, the Fine Arts Department of Thailand began renovations of the ruins, scaling up the project after the site was declared a historical park in 1976.

[7] a The city was founded on Friday, the 6th day of the waxing moon of the 5th month, 1893 Buddhist Era, corresponding to Friday, 4 March 1351 Common Era, according to the calculation of the Fine Arts Department of Thailand.