Muang Si Mahosot is a district of Prachin Buri Province. Formerly known as Khok Pip District, it is an ancient city over 1,200 years old or the 6th Buddhist century onwards. In the past, it used to be an important seaside port. It is a center of prosperity in terms of arts, culture, traditions, and Buddhism. The former Si Mahosot city used to be a large ancient city that was very important. There has been a continuous development of arts and culture. Since before the 11th Buddhist century as a seaside port Therefore, there is a trade and exchange of goods with both China and India. Influenced by Funan culture There is evidence of the excavation of Funan and Roman beads. Which is around 600 - 800 B.C. There are also many animal carvings in the Amaravati style of the 7th - 9th Buddhist centuries at Sa Kaeo. Sa Khwan is considered another ancient city that is old.