Wat Kaeo, or the Crystal Monastery, was located in the southwestern area of the city island in the Pratu Chai Sub-district. It was situated in the Somdet Phra Sri Nakharin Park, part of the Ayutthaya Historical Park. The site of the former monastery is accessible via U-Thong Road. The temple stood north of Wat Khok Madan Yai (defunct) along a canal connected to Khlong Chakrai Yai (1).
The monastery belonged to a cluster of temples located in a residential area in the reign of King Chakkraphat (1548-1569 CE). Thianracha (Chakkraphat) had his princely residence in this area before ascending the throne. The location was important, as most of the palace officials and high ranked persons were living on both sides of the Chao Phraya River between Wat Phutthaisawan and Wat Chai Watthanaram.
The last traces of this temple above the ground level probably disappeared when the Somdet Phra Sri Nakharin Park was constructed. Only a large grass field remains. Its historical background and the exact construction period are unknown, although it is very likely that the former monastery was built in the middle Ayutthaya period.
On the road in front of Wat Kaeo Fa near the Khun Lok Bridge over Khlong Chakrai Yai, there was a fresh market called Khun Lok Market. Khun Lok could be translated as "Ruler of the World", who is Brahma, the Creator. There could be a link between the bridge's name, the market and Wat Jao Phram (Monastery of Lord Brahma) in its immediate vicinity. [1]
Engelbert Kaempfer, a medical doctor working for the Dutch VOC (Verenigde Oost-Indische Compagnie), on his visit to Ayutthaya in June 1690 CE, indicates Wat Kaeo on his sketch.
Wat Kaeo is indicated on a 19th-century map in the same position as Phraya Boran Ratchathanin's 1926 CE map but is denominated as Wat Kaeo Fa (Lit. blue glass). The oldest map indicates the presence of a chedi. Whether or not the monastery had a relation with the child king Yot Fa (reign 1547-1548 CE), also called King Kaeo Fa, is unknown.
The site was in geographical coordinates: 14° 20' 33.51" N, 100° 33' 16.21" E.
Footnotes:
(1) Khlong Chakrai Yai is part of a waterway running through the west of Ayutthaya from north to south. The canal was the extension of Khlong Pak Tho and ran from the Lam Hoei Bridge to the Chakrai Yai Gate opposite Wat Phutthaisawan. The canal was a shortcut through the oxbow of the Lopburi River and connected the old Lopburi River, present Khlong Mueang in the north with - what is today - the Chao Phraya River in the south. Ban Chakrai was a village located on the city island but outside the city walls.