Wat Pom Yai, or the Monastery of the Large Fortress, is an active monastery located off the city island in the western area of Ayutthaya in the Ban Pom Sub-district. The monastery borrowed its name from the old site of Wat Pom Yai, dating to the Ayutthaya period. The site can be accessed via road No 3412.

The old site of Wat Pom Yai stood on the connection canal leading to the Chao Phraya River at Hua Taphan via Khlong Maha Phram. Wat Phra Ngam was situated north, and Wat Pom Noi south. Wat Phukhao Thong was on the opposite side of the connection canal. Between Wat Pom Yai and Wat Pom Noi was a canal called Khlong Wat Pom (some maps have Khlong Worachet), which had a junction with the connection canal leading to the Chao Phraya River. Opposite the mouth of this khlong was another canal leading to Wat Phukhao Thong called Khlong Yai.

In the Ayutthaya era, large wooden forts were in the four directions. The position of one of these forts can be seen on a map by Jacques Nicolas Bellin (1703-1772 CE): Carte du Cours Du Menam Depuis Siam Jusqu'a La Mer Levee sur los Lieux par un Ingenieur Francois and published as plate no. 5 in volume 9 of the 1752 French edition of Abbe Provost's L'Histoire Generale des Voyages.

Nothing remains above ground level of the old Wat Pom Yai. The site was covered with vegetation and somewhat marshy. On the site's eastern side (along Khlong Wat Pom), there was an earthen wall, which may contain remnants of the monastery's outer wall, although this remains a guess.

The site is heavily prone to inundation. For this reason, a new temple with an identical name was established in 2000 CE and, based on the Temple Registration System of the National Office of Buddhism, received its Wisung Kham Sima in 2014 CE.

(View of the entry of Wat Pom Yai - August 2009 CE)

The old monastery figures in the Royal Chronicles of Ayutthaya. Migrating Shans fleeing Burma fought off the Burmese at Nong Pling and advanced to Phitsanulok in 1584 CE (1). Prince Naresuan at Phitsanulok ordered all the border routes sealed to block their escape and received the Thai Yai and their families at Phitsanulok. The Thai Yai were, after that, sent down to Ayutthaya and took residence near Wat Pom.

"On Tuesday, the eleventh day of the waning moon of the eighth month, a year of the tiger, eighth of the decade, the King ordered the Thai Yai families who had come seeking the shelter of the King’s great royal merit, delivered down to the Celestial Capital and Great Royal Metropolis. His Royal Father bestowed utensils and comestibles on all the Thai Yai and then allowed them to take up residence in the vicinity of Pòm Monastery." [1]

The old Wat Pom Yai was in approximative geographical coordinates: 14° 21' 48.33" N, 100° 32' 1.96" E. The new Wat Pom Yai is in: 14° 21' 42.4" N, 100° 31' 57.7" E.


(1) The Royal Chronicles of Ayutthaya have ‘a year of the tiger, eighth of the decade,’ which would be 1566 CE. This input is seemingly not correct.


[1] Cushman, Richard D. & Wyatt, David K. (2006). The Royal Chronicles of Ayutthaya. Bangkok: The Siam Society. p. 96.