Mueang San Buri

Sankha Buri located in Chai Nat province and known locally as San Buri is an historical site located on the old Chao Phraya River, at present the River Noi, and dates back to the Sukhothai period. Prior the Ayutthaya period (1351 - 1767), the town was known as Phraek Sri Racha (Mueang Phraek) and built by King Lerthai in 1317. The town was in the 15th century under Ayutthaya, as Chao Yi Phraya, second son of King Intharacha (r. 1409-1424) of the Suphannaphum dynasty, was named ruler of this city by his father. San Buri was as thus in fact a Muang Luk in the Early Ayutthaya Period. The town was likely already occupied in the Dvaravati Period (6 - 11th Century) and followed by Khmer rule (12th century) thereafter, before becoming a frontier city of Sukhothai. It was an important defensive post in both the Sukhothai and Ayutthaya Kingdoms.
Many of Sanburi's original historical sites were destroyed by modern farming, road building and housing developments. Only a few traces remain in the compounds of Wat Phra Maha That, Wat Phra Kaeo and locations in the vicinity. Remains are mostly from the post-Dvaravati period, when the Khmer ruled Phraek Sri Ratcha. Remnants include sections of the city wall and moat. Most stupa at San Buri were built by copying those of other cities around central Thailand. The stupas at Sanburi could have been built during the middle of the 14th to the beginning of the 15th century, when Sanburi shared a close relationship with Suphan Buri and the two cities were related to the Lanna area. It is believed to be the cities most prosperous period. During the Ayuttaya era, Sanburi had relationships with the Sukhothai dynasty, whilst the change from the U-Thong dynasty to the Suphannaphum dynasty influenced the varied artistic styles of Lopburi and Suphan Buri. The decline of Sukhothai caused San Buri to lose its role as frontier city and therefore its artistic and political significance.
In the reign of King Mongkut (Rama IV) administrative reform took place and the seat of the province was moved to Chai Nat. 

Ayutthaya Historical Research