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Historical profile on arogayasalas, the formidable Khmer hospital temples whose identical ruins span the Angkorian landscape from the ancient imperial capital to its remote frontiers.

Fast Facts

Name: Arogayasala

Culture: Khmer Empire

Era: 1200-1400s CE

Region: Cambodia and Northeastern Thailand

Description: Arogayasalas are a later, standardized temple found throughout the outer reaches of the Khmer Empire. All are built of laterite and consist of an enclosure wall surrounding a central prang temple and bannalai (library), and a squared pond outside of the wall.

Purpose: Arogayasalas were built as part of a reconstruction project by Jayavarman VII and served as hospitals.

Prasat Nong Bua Rai is located near Prasat Phanom Rung, not far from the Cambodia border.
Prasat Nong Bua Rai is located near Prasat Phanom Rung, not far from the Cambodia border.

Life in the dry flatlands of northeastern Thailand follows many of the same patterns today as it did centuries ago. Communities are centered within large tracks of farmland and the sparse population centers are relatively distant from one another. A millennium ago, these small villages were more self-sufficient than reliant on any distant and powerful state.

However, around the year 1200 CE, workers from a newly invigorated Khmer Empire reappeared suddenly in this quiet landscape. They began erecting a multitude of formidable walled stone monuments throughout the entire countryside, a sight that was sure to have stirred these otherwise remote Isaan farming communities.

These stone monuments were arogayasalas, and dozens of these identical Khmer temples were erected throughout the frontier, a clear sign from the capital that the empire was returning.

What is an Arogayasala Hospital Temple?

An arogayasala, commonly referred to as hospitals, medical stations, or nursing homes, were a set of 102 roughly identical temples built in the 12th Century CE by the Khmer Empire. Arogayasalas all follow the same layout plan and are some of the more common sights of Angkorian design throughout the empire’s former territories, particularly in the area that is now northeastern Thailand.

Who Built Arogayasala Hospital Temples?

The Arogayasala temples are spread throughout the reaches of the Khmer Empire’s former domain. They represent a later, standardized type of Khmer Empire temple created as part of a massive infrastructure project initiated by the Khmer king Jayavarman VI.

Angkor Wat in Cambodia, the crowning architectural achievement of the Khmer Empire.
Angkor Wat in Cambodia, the crowning architectural achievement of the Khmer Empire.

The Khmer Empire

While the successive capitals of the established Khmer Empire remained centered around Angkor (modern Siem Reap, Cambodia), the Khmer did have an earlier presence, and even monumental structures, in what is now Isaan (northeastern Thailand). Some of these include Prasat Muang Teui in Yasothon Province and Prasat Phom Phon in Surin Province, both dating from the Chenla Period (6th-9th Centuries CE), several centuries prior to the establishment of a unified Khmer Empire at Angkor.

In later centuries, the Khmer Empire consolidated its power and began to exert influence over the surrounding regions of Southeast Asia,  reaching its territorial height in the reign of King Jayavarman VII. During this time, the empire controlled all of modern Cambodia, Laos, and Thailand, and the recently-defeated Champa nation of southern Vietnam.

Jayavarman VII

Widely considered to be among, if not the greatest of the Khmer emperors, Jayavarman VII was a Mahayana Buddhist king who came to power after a drawn-out war with the Champa Kingdom which devastated the Khmer Empire. Jayavarman had been in exile in Champa for much of his life after his brother has usurped the throne, and only came to power in his 50s.

With his new role as King, Jayavarman instituted many reforms in the name of rebuilding the war-torn empire, including changing the state religion to Mahayana Buddhism and initiating massive public works projects, including building a brand new walled capital city at Angkor Thom and reinforcing the empire’s outer territories with new roads and fortifications. Included among these were the arogayasalas and dharmasalas.  

Design Elements of the Arogayasala

The Bayon monument in Angkor Thom in Cambodia
The Bayon monument in Angkor Thom in Cambodia

Bayon Style

Arogayasalas fall into the Bayon style of the later Khmer Empire, named after the signature crowning monument of Jayavarman VII, the Bayon. This style is characterized by large blocks of laterite as the primary building material and less intricate stone carvings than earlier eras.

Monuments built in the Bayon style include the Bayon itself, along with:

  • Angkor Thom
  • Terrace of the Elephants
  • Ta Phrom
  • Preah Khan
  • Neak Pean
  • Muang Sing
  • arogayasala
  • dharmasala

Bayon Style in the Arogayasala

Because they were built quickly and widely, arogayasalas are essentially a pop-up Angkorian temple. All arogayasalas are constructed primarily of laterite with stucco and sandstone adornments, most of which have faded away in the passing centuries. They all follow the same standard layout and, after coming across more than two or three arogayasalas, you will certainly begin knowing what to expect.

The general plan of all arogayasala hospital temples.
The general plan of all arogayasala hospital temples.

The basic plan of an arogayasala includes:

  • Laterite enclosure wall with an east-facing gopura
  • Single prang shrine in the center
  • Bannalai library southeast of the prang
  • Square, stepped baray pool northeast of the enclosure wall

The Enclosure Wall

The enclosure wall and cruciform gopura of Ku Phanna in Sakon Nakhon province, Thailand.
The enclosure wall and cruciform gopura of Ku Phanna in Sakon Nakhon province, Thailand.

Enclosure walls are common sights in temples of the Hindu-Buddhist tradition, and those of the Khmer Empire were no exception. They serve the purpose of separating the sacred area within from the profane world outside both visibility and physically. In Khmer architecture, many monuments employed several concentric walls.

However, the arogayasala design has only one wall, usually over 1 meter high and built of laterite. They are all slightly rectangular with the east-west wall measuring around 35 meters, while the north-south walls usually measure between 20-30 meters.

All arogayasalas face east with a cruciform gopura entrance. These entrances were usually adorned with a carved sandstone lintel depicting legends from the Hindu or Buddhist tradition. In many arogayasalas, there is a sandstone window to the left of the gopura entrance.

Central Prang Tower

The central prang of Prasat Ta Muen Tot located at the Cambodian border in Thailand's Surin province.
The central prang of Prasat Ta Muen Tot located at the Cambodian border in Thailand’s Surin province.

The prang is the most distinctive feature of an arogayasala and a signature of Khmer design, which was later co-opted by the Thais in their own architecture. The design takes the form of a lotus bud tower and, like Buddhist stupas, is meant to symbolize Mount Meru. In many Khmer Hindu monuments, prangs will appear in threes, signifying the Trimurti, or trinity of Hindu gods.

Arogayasalas feature a single prang in the center of the enclosure with a small, raised entryway facing east. This entryway is often connected to the gopura with a laterite paved walkway. Although many prangs in Khmer monuments will contain Hindu lingams, arogayasalas usually contained a seated Buddha statue.

In more recent times, locals will often place a modern Buddha image within the ruins of the prang for prayer and offerings.

Bannalai Library

The bannalai library at Prang Ku Chaiyaphum with restored relief carvings.
The bannalai library at Prang Ku Chaiyaphum with restored relief carvings.

Bannalais (commonly referred to as libraries) are thought to have housed important documents. However, this is only a speculation and their true purpose is not known.

In the arogayasala design, the bannalai is located in the southeastern corner of the enclosure with its entryway facing west. Bannalais were often adorned with their own carved lintels above the entryway as well.

Baray Reservoir

The stepped baray at Prasat Hin Ban Samo in Sisaket province, Thailand.
The stepped baray at Prasat Hin Ban Samo in Sisaket province, Thailand.

Barays are artificial reservoirs of largely varying sizes found at Khmer sites. While they certainly served practical water storage purposes, many smaller barays existed at Khmer temples as well and were part of ritual bathing practices.

Although many arogayasalas are next to, or very near, a large baray reservoir, each also has its own small baray pond lined with stepped laterite as well. These barays are always located outside the enclosure wall and to the northeast of the gopura entryway. They often appear nearly square, measuring about 10-15 meters on each side.

Origin and Purpose of the Arogayasala Hospital Temple

The arogayasala hospital temple was one part, albeit a massive part, of the public works reconstruction instituted by Khmer King Jayavarman VII. At the time when Jayavarman VII came to the throne, the Khmer Empire had just concluded a devastating war with the neighboring nation of Champa. As a result, not only the capital, but much of their territory was either strained or ruined.

Close-up of the enclosure wall surrounding Prang Ku Ban Khwao in Mahasarakham province, Thailand.
Close-up of the enclosure wall surrounding Prang Ku Ban Khwao in Mahasarakham province, Thailand.

This prompted reconstruction effort because, as an inscription — and likely self-propaganda piece — known as the Saifong Inscription (K. 368) states, the king suffered from the pain of his people more than that of himself. In another inscription found at the Ta Phrom temple, just east of the Angkor Thom city wall, and also built by Jayavarman VII, the text speaks of the king ordering the construction of 102 arogayasala hospital temples throughout the empire.

Four of these arogayasalas are in the direct vicinity of Angkor Thom. The majority of them are within modern Cambodia, and about 30 of them are in modern Thailand. These hospital temples were built at a time when the primarily-Hindu state had recently taken up Mahayana Buddhism as its state religion at the direction of the king, leading to this massive influx of Buddhist temples arising throughout the far reaches of the empire.

Central prang and rear of bannalai from outside the wall of Ku Santarat in Mahasarakham province, Thailand.
Central prang and rear of bannalai from outside the wall of Ku Santarat in Mahasarakham province, Thailand.

The overgrown stone and laterite structures dotting the sparse landscapes today are not indicative of the extent of the original arogayasala. Like even the great palaces at Angkor, which have long since disappeared, the arogayasala plan originally included a complex of wooden buildings surrounding the walled stone temple. However, with the centuries, those have also faded away.

The term “arogayasala” translates directly as ‘hall devoid of disease’ and served not only as Buddhist temples, but as hospitals which practiced traditional Khmer medicine, which had been sufficiently advanced enough to warrant even the Chinese sending emissaries to document their practices and recipes.

As a secondary purpose, these standardized temples also served as a means of power projection throughout the recently reinvigorated Khmer Empire. Seeing these formidable constructions being rapidly built in all corners of Khmer territory would no doubt send a message both to the people and neighboring states that the Khmer Empire under Jayavarman VII was once again at full strength.

Modern Buddha shrine within the prang of Ku Phanna in Sakon Nakhon province, the northernmost Khmer ruin in Thailand.
Modern Buddha shrine within the prang of Ku Phanna in Sakon Nakhon province, the northernmost Khmer ruin in Thailand.

Legacy of the Arogayasala Hospital Temple

Jayavarman’s construction projects left a tangible mark on the region, as well as further cementing Buddhism throughout Khmer territory. While Jayavarman VII made vast improvements to the state of the empire, and perhaps the most notable mark of the Khmer Empire on the future of Southeast Asia as a whole, the end of his rule also marked the beginning of the Khmer Empire’s decline.

Ruined bannalai library at Prasat Chom Phra in Surin province, Thailand.
Ruined bannalai library at Prasat Chom Phra in Surin province, Thailand.

The arogayasalas throughout the empire, along with Jayavarman’s other works, cost the empire massively in both construction and operation. Likewise, his social reforms would begin to destabilize the society and lead to turmoil within the leadership, resulting in many outer territories such as Champa, Sukhothai, and Ayutthaya breaking away.

As the empire fell apart, these monumental buildings in their outer frontiers were left abandoned, often being forgotten or deconstructed for use elsewhere. However, dozens of these arogayasalas still line the fields and forests of northeastern Thailand’s countryside waiting to be rediscovered.

Notable Examples of Arogayasala Hospital Temples

Angkor Hospital Chapel
Siem Reap, Cambodia
13.44532, 103.88057
Angkor hospital chapel is one of four arogayasalas located nearby the imperial capital at Angkor Thom and significantly more complex than the general arogayasalas in the outer empire.

Prasat Ku Phanna
Sakon Nakhon, Thailand
17.44277, 103.55727
Ku Phanna is the northernmost extant ruin of the Khmer Empire.

Prang Ku
Roi Et, Thailand
16.07741, 103.73466
Located near the capital of Roi Et province, the Prasat Prang Ku arogayasala has undergone significant reconstruction.

Kuti Ruesi
Nakhon Ratchasima, Thailand
15.2119, 102.4983
Standing just south of the gate to Phimai and marking the end of the Dharmasala Route, this arogayasala is made from carved sandstone rather than laterite.

Prasat Ta Muen Tom
Surin, Thailand
14.35396, 103.26161
This arogayasala site in an important pass through the Dangrek Mountains along the Dharmasala Route, near other important Khmer monuments at the modern Thai-Cambodian border.

Fast Facts


Capital of the Khmer Empire, located near modern-day Siem Reap, Cambodia.

Angkor Thom
Walled city and final capital of the Khmer Empire built by Jayavarman VII.

Angkor Wat
Signature monument and Hindu temple mountain built by Khmer king Suryavarman II.

Standardized hospital temple design built throughout the Khmer Empire by Jayavarman VII.

Khmer monument commonly referred to as libraries and thought to house important documents, however, their true purpose is unknown.

Signature monument of Jayavarman VII standing at the center of Angkor Thom. The original name was Jayagiri (“Victory Monument”).

Bayon style
Khmer architectural style lasting from 1180-1230 and characterized by laterite construction, less intricate carvings, and Buddhist themes.

An Indianized Hindu kingdom in ancient Vietnam known for constructing Tháp Chàm, their iconic Cham Towers dedicated to Shiva and other Hindu deities.

Chenla Period
Early period (6th-9th Centuries CE) of independent Khmer states before being united into the Khmer Empire by Jayavarman II.

“Fire house” temple design built along the Khmer Empire’s Angkor-Phimai road by Jayavarman VII.

Dharmasala Route
Important road from Angkor to Phimai and lined with 17 dharmasalas.

Entrance building to an important structure.

Common name for the northeastern region of Thailand.

Jayavarman VII
Mahayana Buddhist king of the Khmer Empire from 1181–1218 who conquered Champa, built Angkor Thom, and initiated massive engineering projects to rebuild the kingdom.

Khmer Empire
Hindu-Buddhist kingdom which ruled much of Southeast Asia from their capital at Angkor.

Red clay-like soil which hardens when dry and is used in many types of construction.

Mahayana Buddhism
A sect of Buddhism focused on the reverence of bodhisattvas.

Mount Meru
The metaphysical mountain said to represent the structure of the universe in Hindu-Buddhist cosmology.

Muang Sing
Walled Angkorian city on the western edge of ancient Khmer territory, near the Burmese border of of modern Thailand.

Signature monument of the Khmer consisting of a tower representing a lotus bud and housing a Hindu lingam or Buddhist idol. The design was later appropriated by the Thais in their monuments.

Thai and Khmer word meaning “castle”, “tower”, or “temple” most often used in reference to Khmer stone prangs and ruins, and occasionally for Thai brick stupas.


Have you had the chance to visit any of the remote Khmer ruins in northeastern Thailand? Are there any that we should examine in-depth with a full Lost Cities Travel Guide? I look forward to reading your thoughts below!

Benjamin Williams

Hi all, my name is Ben. I’m a native Michigander with a passion for human culture and new places, and more than that, new experiences. I have degrees in archaeology and writing, pursuing a career in the latter. However, I never quite lost that fascination for archaeological theory. For the past 11 years, I’ve been living and travelling between Asia, Europe, and North America, documenting ancient sites and the peoples who built them, and then adapting them into practical archaeological travel information at


  • jonicaggiano says:

    It is amazing the amount of history that this comprehensive post shows. The photography really enhances the history. It is nice to see how much care is being taken to preserve these beautiful example of the Country’s history. Thank you. Blessings and love to you. Joni

  • Nepal Kailash Trekking says:

    Brilliant photo shot, its amazing. Thank you so much Ben for your posting.

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