Directly across the road from Wat Ratchaburana lies the temple of Wat Mahathat. The temple was probably built in the early days of Ayutthaya in the late 14th century by King Borommaracha I. The story goes that the king had a revelation, and relics of the Buddha then suddenly appeared. The temple was built to house the relics. The name, "Wat Mahathat" literally means "Monastery of the Great Relic" and when the collapsed central tower was excavated in the mid-1950s a small reliquary containing a piece of bone about the size of a grain of rice was found.
The temple served as the ceremonial heart of the city, and so was the site of many important events. In addition to being the central royal temple of the empire, it was also the home of the supreme patriarch of the 'city-dwelling' sect. Little remains today except the core of the old prang and a few smaller chedis. It is nonetheless an impressive compound.
There is a fee of 50 Baht (1.30 USD) to enter the grounds of Wat Mahathat. The temple is open from 8:30 am to 5:00 pm every day.