Wat Pa Fai is mentioned in the epic poem "Khun Chang Khun Phaen": Phlai Kaeo received an order from the king to retake Chiang Thong from the Lao (Chiang Mai).
"They marched to the mouth of the Bang Lang Canal and crossed over to the side with houses. Porters dropped the loads which had bounced up and down until the frames loosened. They untied the shoulder poles to take a rest. As soon as they had eaten some winged beans, Phlai Kaeo ordered the troops to march on to the start of the route they would travel. ‘Unharness the elephant and horses and wait for me at the sala of Wat Pa Fai.’ The troops saluted their chief and moved off immediately." [1]
From the text, we can deduce that the northern route toward Kamphaeng Phet started at Wat Pa Fai. Wat Pa Fai must have been a temple of some importance. Locals said that the size of the temple grounds was between 30 and 35 Rai. (2)
The temple was situated on a bend of the Lopburi River at a confluence of waters. Not forget the Lopburi River was in the 17th century the main river surrounding the island of Ayutthaya, called Maenam. (see Bellin's map).
I did not found out yet where the story was born, but locals in the vicinity of Wat Pa Fai stated that on a day King Naresuan (reign 1590-1605 CE) went into war, a monk called "Bamrung" recited for him "Phahung" (the Phuttha Chaya Mongkhon kata) at Wat Pa Fai. Naresuan obtained, after that, victory over his enemies. This story could also be linked to Wat Pa Fai being positioned at the starting point of the northern (war) route. (3) [2]
Wat Pa Fai is also mentioned in the Chronicles of Ayutthaya when the northern Burmese army came down from Kamphaeng Phet in 1766 CE to attack the City of Ayutthaya. General Nemiao advanced with his land and boat forces to set up a main stockade near Wat Pa Fai in the present Ban Khai (village of the camp) on the western (right) bank of the Lopburi River.
"Meanwhile, Nemiao, the grand chief marshal, accordingly led his land army and his boat army on down from the Municipality of Kamphaeng Phet to join up with the army of Noekuancòbo and of the front brigades which had established a stockade at the Municipality of Nakhòn Sawan. Then he accordingly led them on down to the Holy Grand Metropolis and advanced to establish his main stockade in the vicinity of the Monastery of the Cotton Groves at the Mouth of the Merging Rivers." (4) [3]
The Siamese set up stockades in the Pho Sam Ton fields to attack the Burmese defences near Wat Pa Fai. The chronicles stated that "On that day, the groups of troops were so numerous they covered the entire surface of the plain.".
The Burmese drove back their horses across the river and sought refuge in their enclosure. The Siamese turned towards the Burmese stockade, but were received with a cannonade. Five or six Siamese were killed, and the Siamese army retreated to their own enclosures. In the evening, the Siamese ended the campaign and returned to the city. It was an abysmal performance, which would cost Ayutthaya dearly after.
"When chief marshals, important persons and unimportant persons, advanced forth to attack the Burmese stockades which had been established at the Monastery of the Cotton Groves at the Mouth of the Merging Rivers and had their men plait strips of sisuk bamboo [together into lattices] and carry [the lattices] away with them on their backs. “Regardless of where you build your stockades each person will take his sisuk bamboo [lattices], set them up in a line so they are close together, and then will dig up piles of dirt to take to hide [the lattices] to form stockades.” Now so many people advanced that day they filled the plain. On the edges of whatever place the chief marshals had their litters halted, they accordingly all halted together and waited to go on. When [the marshals] saw Burmese [from the stockade] of the Monastery of the Cotton Groves riding many horses across the river and heading towards their main stockade on the western banks, they thereupon drove their people forward to attack the Burmese. The Burmese within the stockade thereupon fired their guns forth, hitting and felling five or six people. All those people [belonging to the marshals] accordingly retreated [to their stockades] without exception. When it was evening they accordingly ended the campaign and came back." [4]
Prince Damrong Rajanubhab mentions Wat Pa Fai in the recount of the 1766-67 CE Burmese incursion in one of his documents.
"As regards the forces under Nemiao Sihabodi which came down from the north, of those that came down from Muang Nakhon Sawan, some proceeded by way of Muang Chainat and some by way of Muang Uthai Thani and Muang San. They entered the boundaries of the circle of the capital in the third Siamese month (February) in the year of the cock, about the same time as the forces under Mang Maha Noratha. They established their camp at Wat Pa Fai at the mouth of the Phra Prasop river on the north side of the city." (5)[5]
The ruins of Wat Pa Fai were dismantled by the locals in the early 50s as there was a demand for bricks in expanding Bangkok. Boats and trucks came to the area to pick up all suitable construction materials. Not only bricks were broken out, but also large blocks of laterite, which were used for the foundation of the monastic buildings.
The former monastery was in geographical coordinates: 14° 26' 1.15" N, 100° 33 '9.71" E.