The exact date of the establishment of Wat Maha That is difficult to assess.
The Luang Prasoet version of the Royal Chronicles of Ayutthaya put its construction in
736 Chula Sakarat (CS) or 1374 of the Christian Era, during the reign of King
Borommaracha I (r. 1370-1388), somehow 23 years after the establishment of
Ayutthaya. The chronicles mention that the central prang had a height of 46 meter.