The Wat Mahathat is located in the center of Ayutthaya Historical Park, between Chi Kun Road and Naresuan Road in the northeast corner of Phra Ram Park.[1]
"In the Year of the Tiger 736 C.S. Somdet Phra Borommarachathirat and Phra Mahathera Thammakanlayan built the great, glorious, holy, jewelled reliquary (Phra Si Rattana Mahathat) east of the palace (the Royal gable of the lion). He rose 19 wa in height and equipped with a nine-membered tip that is another 3 wa in height."
His nephew and successor Ramesuan (1369-1370, 1388-1395) expanded the site in 1384 to build a great temple, while he was here as a monk between his throne offices. During this time the temple got its present name.[3]