Wat Lai is an ancient temple situated along the Bang Kham River, believed to have been established during the Sukhothai period, around 1257-1357 CE. It reached a peak of prosperity during the Ayutthaya period, particularly under the reign of King Borommakot, who ordered a major restoration. The most prominent legend involves Phra Sri Arn and the story of Thao Montha, an elderly man who devoted his life to merit-making in hopes of meeting the future Buddha. According to lore, the Bodhisattva eventually descended to Earth as a monk and resided at this temple. After his passing, his remains reportedly turned into copper, leading the locals to cast a sacred image for worship. Although a fire damaged the image during the reign of King Rama V, the King ordered its complete restoration due to the profound faith of the people. This has established Wat Lai as a central hub for the belief in the era of Phra Sri Ariyamettaya to this day.