Wat Pa Thon or the "Monastery of the Thon Market" was located on the city island, outside the Historical Park in the east of the city, at present Ho Rattanachai sub-district. “Pa Thon” was an area in Ayutthaya where the “thon” - a type of Thai drum - and other musical instruments were made. 
The "thon" is a Thai goblet drum, a single headed drum. The head is around 20 cm in diameter. The drum has a ceramic or hard wooden body. The "thon" lies on the player's lap and is played with the right hand. The drum gives a low pitch. It is often played simultaneously with another instrument called "ramana". The latter is held in the left hand and gives a high pitch. Together they are known as "thon-ramana" and played as a pair in Central Thai classical music, usually in the Khruang Sai Ensemble, a stringed ensemble. (1)
The monastery was situated between Khlong Nai Kai (present Khlong Makham Riang) and the Front city canal (present Pa Sak River). To its north stood Wat Khok Dokmai, while in the south was Wat Khok Khamin. Wat Saphan Ngern was situated in the west, opposite Khlong Nai Kai. "Pratu Jao Jan", a gate in the city wall, was located to its east.
There is still some brickwork visible of the monastic structure. Old bricks are shattered all over the area.
Historical data about the monastery and its construction are unknown.
The site is indicated on Phraya Boran Rachathanin's (PBR) map drafted in 1926, but it is called Ban Pa Thon and as thus not referring to a temple. Following PBR the structure stood along a brick road, an extension of the Pa Thon Rd. A few meters south of this brick road, there must once have been a canal, which was part of a larger waterway connecting the Rear Palace with the Front city canal.
(1) De La Loubère wrote the following about this instrument is his "A New Historical relation of the Kingdom of Siam": "The people do also accompany the voice in the evening into the courts of the houses, with akind of drum called Tong. They hold it with the left hand, and strike it continually with the right hand. 'T is an earthen bottle without a bottom, and which instead thereof is covered with a skin tyed to the neck with ropes."
 Internet source http://www.ayutthayastudy.org retrieved on 16 July 2010 - Patone Road Or Dejavudh Road? by Patt Taengpun.  Internet source www.culture.go.th/research/musical retrieved on 16 July 2010.  Internet source www.thaimusic.net retrieved on 16 July 2010.
Text, photographs & map by Tricky Vandenberg - July 2010