Inner Cambodia was a historical region in present-day
Cambodia
Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...
that was under the direct rule of
Siam
Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...
(Thailand) between 1794 and 1907. It covered much of north-western Cambodia, and included, most significantly, the cities of Phra Tabong, Siemmarat and Si Sophon (now known by the Khmer names
Battambang
Battambang (, Romanization of Khmer#UNGEGN, UNGEGN: ) is the capital of Battambang province and the List of cities and towns in Cambodia, third largest city in Cambodia. The city is situated on the Sangkae River, which winds its way through t ...
,
Siem Reap
Siem Reap (, ) is the second-largest city of Cambodia, as well as the capital and largest city of Siem Reap Province in northwestern Cambodia.
Siem Reap possesses French-colonial and Chinese-style architecture in the Old French Quarter ...
, and
Serei Saophoan). The region was ruled by a Bangkok-appointed governor who held the title
Aphaiphubet
Aphaiphubet () is a Thai noble title granted to some governors of Battambang, who acted as rulers of Inner Cambodia during the period of Siamese rule from 1794 to 1907. Past titleholders all came from what is now the Abhayavongsa family.
Holde ...
, and was incorporated under the ''
monthon
''Monthon'' (), also known as ''Monthon Thesaphiban'' (; Mṇṯhl Theṣ̄āp̣hibāl; , ), were Administrative divisions of Thailand, administrative subdivisions of Thailand at the beginning of the 20th century. The Thai word ''monthon'' is a tr ...
'' administrative system in 1891, becoming known as Monthon Burapha in 1900. The territory remained under Thai control until 1907, when it was
ceded to France and incorporated into
French Indochina
French Indochina (previously spelled as French Indo-China), officially known as the Indochinese Union and after 1941 as the Indochinese Federation, was a group of French dependent territories in Southeast Asia from 1887 to 1954. It was initial ...
. The region was again briefly annexed by
Thailand during the Second World War from 1941 to 1946.
Establishment of Siamese rule
In the late 18th century,
post-Angkor Cambodia was much weakened against its neighbours Siam to the west and Vietnam to the east, who
fought for influence over the smaller country. Following factional struggles in the 1770s, a pro-Siam nobleman named
Baen
Baen Books () is an American publishing house for science fiction and fantasy. In science fiction, it emphasizes space opera, hard science fiction, and military science fiction. The company was established in 1983 by science fiction publisher an ...
brought Prince
Ang Eng, the only male survivor of the Cambodian royal family, to take refuge in Bangkok under the Siamese King
Rama I
Phutthayotfa Chulalok (born Thongduang; 20 March 1737 – 7 September 1809), also known by his regnal name Rama I, was the founder of the Rattanakosin Kingdom (now Thailand) and the first King of Siam from the reigning Chakri dynasty. He asc ...
. Baen received the title Chaophraya Aphaiphubet from the Thai court, and was established as the ''de facto'' ruler in the Cambodian royal capital of
Oudong
Oudong (; also romanized as Udong or Odong) is a former town of the post-Angkorian period (1618–1863) situated in present-day ''Phsar Daek'' Commune, Kampong Speu Province, Cambodia, near the border between Kandal Province and Kampong Chhnang Pr ...
.
When the Prince was allowed to return to Cambodia to assume the throne in 1794, Rama I had the northwestern area of the country, which constituted most of its border with Siam, placed under the control of Baen, who was instituted as governor of the region, based in Battambang (known in Thai as Phra Tabong). Siem Reap (Siem Rap in Thai, later changed to Siemmarat), the site of the ancient Khmer capital of
Angkor
Angkor ( , 'capital city'), also known as Yasodharapura (; ),Headly, Robert K.; Chhor, Kylin; Lim, Lam Kheng; Kheang, Lim Hak; Chun, Chen. 1977. ''Cambodian-English Dictionary''. Bureau of Special Research in Modern Languages. The Catholic Uni ...
, was the other major town in the region, the most fertile in Cambodia. This served a twofold purpose, strengthening Siam's control over the frontier while removing Baen from the conflict in Oudong, where his rule was deeply unpopular.
The region, whose governor ruled autonomously according to Cambodian customs but reported directly to Bangkok, became known to the Thais as Inner Cambodia, while the remainder, Outer Cambodia, continued to be ruled by the
Cambodian monarch, who was at various times under
tributary
A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...
status to Siam, Vietnam, or both.
Following Baen's death in 1809 shortly after that of Rama I, the new Thai king
Rama II
Phutthaloetla Naphalai (born Chim; 24 February 1767 or 1768 – 21 July 1824), also known by his regnal name Rama II, was the second King of Siam from the Chakri dynasty, ruling from 1809 to 1824. In 1809, Itsarasunthon succeeded his father R ...
named Baen's son as the new governor at Phra Tabong, inheriting the
Aphaiphubet
Aphaiphubet () is a Thai noble title granted to some governors of Battambang, who acted as rulers of Inner Cambodia during the period of Siamese rule from 1794 to 1907. Past titleholders all came from what is now the Abhayavongsa family.
Holde ...
title. While Khmer sources would later dispute the act, stating that the arrangement was originally understood to be limited to Baen's lifetime, it established the hereditary succession which placed rule over the region in the hands of the
Abhayavongsa family for much of the following century, except for the period between 1834 and 1839, when the Thai court granted the role to the Cambodian prince
Ang Im.
Phra Tabong served as an outpost from which Siam launched military expeditions into Cambodia, especially during its wars with Vietnam in
1833–1834 and
1841–1845, during the reign of
Rama III
Nangklao (born Thap; 31 March 1788 – 2 April 1851), also known by his regnal name Rama III, was the third king of Siam from the Chakri dynasty, ruling from 21 July 1824 to 2 April 1851.
Nangklao was the eldest surviving son of King Rama II. ...
. The Thai military commander
Chaophraya Bodindecha, who led the campaigns, oversaw the reconstruction of the city and its fortifications from 1837 to 1838, and did so in Siemmarat as well. He also founded the towns of Mongkhon Buri (now
Mongkol Borey) and Si Sophon (
Serei Saophoan), the latter of which was mainly populated by Lao forced settlers following Siam's conquest of
Vientiane
Vientiane (, ) is the capital city, capital and largest city of Laos. Situated on the banks of the Mekong, Mekong River at the Thailand, Thai border, it comprises the five urban districts of Vientiane Prefecture and had a population of 840,000 ...
in the
1826–1828 war.
Colonial pressures

With
France's colonial expansion into Southeast Asia in the second half of the 19th century, the
French protectorate of Cambodia
The French protectorate of Cambodia (; ) refers to the Kingdom of Cambodia when it was a French protectorate within French Indochina, a collection of Southeast Asian protectorates within the French colonial empire. The protectorate was establi ...
was established in 1863. After a few years of diplomatic manoeuvring over Cambodia's tributary status, the
Franco-Siamese treaty of 1867 was concluded in Paris, in which Siam recognized the protectorate and relinquished its claims to suzerainty over Cambodia, while France recognized Siam's territorial claims over Battambang and Siem Reap, including the monument of
Angkor Wat
Angkor Wat (; , "City/Capital of Wat, Temples") is a Buddhism and Hinduism, Hindu-Buddhist temple complex in Cambodia. Located on a site measuring within the ancient Khmer Empire, Khmer capital city of Angkor, it was originally constructed ...
(though some officials of
French Indochina
French Indochina (previously spelled as French Indo-China), officially known as the Indochinese Union and after 1941 as the Indochinese Federation, was a group of French dependent territories in Southeast Asia from 1887 to 1954. It was initial ...
had opposed Siam's claims). Nevertheless, the French expressed continued interest in the ruins of Angkor, which had been popularized in the Western imagination by the writings of
Henri Mouhot
Alexandre Henri Mouhot (15 May 1826 – 10 November 1861) was a French naturalist and explorer of the mid-19th century. He was born in Montbéliard, Doubs, France, near the Swiss border. He died near Luang-Prabang, Laos. He is remembered mostly ...
following his travels there in 1860.
Siam's King
Mongkut
Mongkut (18 October 18041 October 1868) was the fourth Monarchy of Thailand, king of Siam from the Chakri dynasty, titled Rama IV. He reigned from 1851 until his death in 1868.
The reign of Mongkut was marked by significant modernization ini ...
(Rama IV) also showed interest in the monuments, and also in 1860 he had ordered the dismantling of a small Khmer temple for reconstruction in Bangkok. Some 2,000 labourers were conscripted for the project, which was terminated after a band of local Khmers emerged from the jungle to attack the party and murdered the Siam-employed officials overseeing the work. Later, in 1867, Mongkut would commission a different representation of Angkor in Bangkok, and had a scale model of
Angkor Wat
Angkor Wat (; , "City/Capital of Wat, Temples") is a Buddhism and Hinduism, Hindu-Buddhist temple complex in Cambodia. Located on a site measuring within the ancient Khmer Empire, Khmer capital city of Angkor, it was originally constructed ...
built in the royal temple of
Wat Phra Kaew
Wat Phra Kaew (, , ), commonly known in English as the Temple of the Emerald Buddha and officially as Wat Phra Si Rattana Satsadaram, is regarded as the most sacred Wat, Buddhist temple in Thailand. The complex consists of a number of buildings ...
in the
Grand Palace
The Grand Palace (, Royal Institute of Thailand. (2011). ''How to read and how to write.'' (20th Edition). Bangkok: Royal Institute of Thailand. . ) is a complex of buildings at the heart of Bangkok, Thailand. The palace has been the officia ...
instead.
Despite its location in Siam, the French were able to secure permission for exploration and study of Angkor's sites, and developed Angkorian art and architecture into a symbol of Cambodian national identity. These seemingly academic undertakings also served political purposes, helping to strengthen France's colonial agenda and further the argument for the region to be returned to Cambodia.
As colonial pressure increased towards the end of the century, King
Chulalongkorn
Chulalongkorn (20 September 1853 – 23 October 1910), posthumously honoured as King Chulalongkorn the Great, was the fifth king of Siam from the Chakri dynasty, titled Rama V. Chulalongkorn's reign from 1868 until his death in 1910 was cha ...
(Rama V) implemented centralizing reforms and introduced the
Monthon Thesaphiban administration system to bring Siam's fringe towns and cities (''
mueang
Mueang ( Ahom: 𑜉𑜢𑜤𑜂𑜫; ''mɯ̄ang'', ), Muang ( ''mɯ́ang'', ), Möng ( Tai Nuea: ᥛᥫᥒᥰ ''möeng''; ''móeng'', ), Meng ( zh, c=猛 or 勐) or Mường (Vietnamese) were pre-modern semi-independent city-states or princip ...
'') and tributaries under Bangkok's direct control, effectively annexing them into Thai territory in line with the Western concept of territorial sovereignty. Inner Cambodia, now comprising the ''mueang'' of Phra Tabong, Siemmarat, Si Sophon and Phanom Sok (
Phnom Srok), was established as Monthon Khamen in 1891. Phraya Maha-ammattayathibbodi (Run Siphen) was posted as commissioner to the new ''monthon'', based in Si Sophon.
However, the conflict with France soon erupted into the
Franco-Siamese crisis of 1893
The Franco-Siamese crisis of 1893, known in Thailand as the Incident of Rattanakosin Era 112 (,
, ) was a conflict between the French Third Republic and the Kingdom of Siam. Auguste Pavie, French vice-consul in Luang Prabang in 1886, was the c ...
, which resulted in Siam being forced to cede extensive territory to France. Inner Cambodia remained under Siam's control, though the
Franco-Siamese treaty of 1893 demanded that Siam demilitarize the area. With the Thai government's wariness over further French designs, little effort was made to support development and fully implement reforms in the region, which was renamed to Monthon Tawan-ok in 1899 and Monthon Burapha (both meaning 'east ''monthon) in 1900.
The situation continued until the
Franco-Siamese treaty of 1907 was concluded, with Siam ceding control of the remaining area of Inner Cambodia to France in exchange of the towns of
Trat
Trat (, ), also spelt Trad, is a town in Thailand, capital of Trat province and the Mueang Trat district. The town is in the east of Thailand, at the mouth of the Trat River, near the border with Cambodia.
Etymology
''Trat'' is believed to d ...
and
Dan Sai, which had been under French occupation since 1904, as well as the ending of French
extraterritoriality
In international law, extraterritoriality or exterritoriality is the state of being exempted from the jurisdiction of local law, usually as the result of diplomatic negotiations.
Historically, this primarily applied to individuals, as jurisdict ...
over Asian subjects.
The last governor of Battambang under Siamese rule, , relocated to
Prachin Buri, where he commissioned the construction of the
Chao Phraya Aphaiphubet Building, regarded as a sister building of the Governor's Residence in Battambang, which he had also commissioned just prior to the handover. Both buildings now serve as museums.
World War II

In the prelude to the
Pacific theater
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the continen ...
of
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
, the nationalist government of Thai Prime Minister Plaek Phibunsongkhram
invaded French Indochina in 1940 to pursue its irridentist
pan-Thai ideology and reclaim what it regarded as
Thailand's lost territories. The war concluded in 1941 with an armistice negotiated by Japan, in which France ceded the areas around Battambang and Siem Reap (north and west of Angkor), which were incorporated as the Thai territories of
Phra Tabong province and
Phibunsongkhram province, respectively, as well as those now part of
Preah Vihear province
Preah Vihear (, UNGEGN: ''Preăh Vĭhar'', ALA-LC: ''Braḥ Vihār'' ; lit. 'sacred sanctuary') is a province (''khaet'') of Cambodia. It borders the provinces of Oddar Meanchey and Siem Reap to the west, Kampong Thom to the south and Stung Tr ...
and Laos'
Champasak province
Champasak (or Champassak, Champasack – Laotian language, Lao: ຈຳປາສັກ ) is a province in southwestern Laos, near the borders with Thailand and Cambodia. It is 1 of the 3 principalities that succeeded the Laos, Lao kingdom of Lan ...
(becoming
Nakhon Champasak province) and
Sainyabuli province (which became
Lan Chang province).
Following Japan's defeat, Thailand relinquished these claims and returned the territories in 1946 as a condition for its admission into the
United Nations
The United Nations (UN) is the Earth, global intergovernmental organization established by the signing of the Charter of the United Nations, UN Charter on 26 June 1945 with the stated purpose of maintaining international peace and internationa ...
.
See also
*
Cambodia–Thailand relations
Notes
References
{{Former provinces of Thailand
History of Cambodia
History of Thailand
Cambodia–Thailand relations
Territorial evolution
Former provinces of Thailand
1907 disestablishments in Siam
1795 establishments in Asia
Annexation