The ancient prehistoric civilization flourished in the western part of Thailand dates back to several tens of thousand years.  From Kanchanaburi province especially in the basin of the two branches of the Kwai Yai and Noi rivers, many archaeological objects have been discovered.

One of the most important sites found in the Kwai Noi River basin is an ancient city site named Muang Sing.  The important discoveries made near the ancient city remains include prehistoric  human skeletons together with metal tools, vessels and ornaments; brick bases of the Dvaravati period architecture; and the laterite ruins of the13th century.

This Muang Sing must have been an important outpost of Angkor as it was mentioned in the Prasat Phra Khan inscription made during the reign of King Jayavarman VII.

At present, Muang Sing on the bank of the Kwai Noi River is included in Muang Sing sub-district.  The vestiges of the ancient city comprise several layers of rectangular walls and moats, having Prasat Muang Sing in the middle.  Other three lesser monuments in ruins are also found in the area.  From the main monument has been discovered a number of Mahayana Buddhist images.

The three lesser monuments could have been built in the same period as Prasat Muang Sing in the 13th century, in the area which had been on the important communication route that connected central Thailand to Lower Burma.