:Inner Cambodia

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{{efn|Also spelled Ben.}} brought Prince Ang Eng, the only male survivor of the Cambodian royal family, to take refuge in Bangkok under the Siamese King Rama I. 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.{{cite journal |last1=Chandler |first1=David P. |title=Cambodia's Relations with Siam in the Early Bangkok Period: the politics of a Tributary State |journal=Journal of the Siam Society |date=1972 |volume=60 |issue=1 |pages=153–169 |url=https://thesiamsociety.org/wp-content/uploads/1972/03/JSS_060_1d_Chandler_CambodiaRelationsWithSiamInEarlyBangkokPeriod.pdf}}

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,{{efn|{{lang|th|เสียมราบ}}}} later changed to Siemmarat), the site of the ancient Khmer capital of Angkor, 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 status to Siam, Vietnam, or both.{{cite magazine |last1=นานา |first1=ไกรฤกษ์ |author-mask= ไกรฤกษ์ นานา |title=วารสาร นักล่าอาณานิคม ตีแผ่ ทำไมสยามสละ นครวัด ? |url=https://www.silpa-mag.com/history/article_31756 |magazine=Silpa Wattanatham |access-date=18 February 2025 |language=th |date=18 February 2023 |orig-date=September 2006}}

Following Baen's death in 1809 shortly after that of Rama I, the new Thai king Rama II named Baen's son as the new governor at Phra Tabong, inheriting the Aphaiphubet 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. 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.{{cite journal |last1=Wilson |first1=Constance M. |title=The Nai Köng of Battambang, 1824-68 |journal=Royalty and Commoners |date=1 January 1980 |pages=66–72 |doi=10.1163/9789004643826_009|isbn=978-90-04-64382-6 }}{{cite thesis |last1=Rungswasdisab |first1=Puangthong |title=War and trade: Siamese interventions in Cambodia, 1767-1851 |type=PhD thesis |url=https://ro.uow.edu.au/articles/thesis/War_and_trade_Siamese_interventions_in_Cambodia_1767-1851/27653409 |publisher=University of Wollongong |pages=103–104 |language=en |date=1995}} He also founded the towns of Mongkhon Buri{{efn|{{lang|th|มงคลบุรี}}}} (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 in the 1826–1828 war.{{cite magazine |last1=ภักดีคำ |first1=ศานติ |author-mask=ศานติ ภักดีคำ |title=เจ้าพระยาบดินทรเดชา (สิงห์ สิงหเสนี) กับบทบาทสร้างเมืองใหม่ในกัมพูชา |magazine=Silpa Wattanatham |date=11 February 2023 |orig-date=September 2017 |url=https://www.silpa-mag.com/history/article_43224 |access-date=2 March 2025 |language=th}}

File:Wat Phra Sri Rattana Satsadaram 06.jpg at Wat Phra Kaew, completed in 1882]]

With France's colonial expansion into Southeast Asia in the second half of the 19th century, the French protectorate of Cambodia 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{{cite journal |last1=Lee |first1=Sang Kook |title=Siam Mismapped: Revisiting the Territorial Dispute over the Preah Vihear Temple |journal=South East Asia Research |date=March 2014 |volume=22 |issue=1 |page=44 |doi=10.5367/sear.2014.0196}} (though some officials of French Indochina had opposed Siam's claims).{{cite journal |last1=Briggs |first1=Lawrence Palmer |title=Aubaret and the Treaty of July 15, 1867 between France and Siam |journal=The Far Eastern Quarterly |date=1947 |volume=6 |issue=2 |pages=122–138 |doi=10.2307/2049157|jstor=2049157 }}{{cite journal |last1=Thomson |first1=R. Stanley |title=Siam and France 1863-1870 |journal=The Far Eastern Quarterly |date=November 1945 |volume=5 |issue=1 |pages=28–46 |doi=10.2307/2049449|jstor=2049449 }} 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 following his travels there in 1860.{{cite journal |last1=Falser |first1=Michael |title=The first plaster casts of Angkor for the French métropole: From the Mekong Mission 1866-1868, and the Universal Exhibition of 1867, to the Musée khmer of 1874 |journal=Bulletin de l'École française d'Extrême-Orient |date=2012 |volume=99 |issue=1 |pages=49–92 |doi=10.3406/befeo.2012.6152}}{{cite book |last1=Falser |first1=Michael |title=Angkor Wat – A Transcultural History of Heritage |chapter=I. Lost in Translation? The Mekong Mission of 1866 and the Plaster Casts from Angkor at the Parisian Universal Exhibition of 1867 |date=2020 |volume=1 |pages=57–88 |doi=10.1515/9783110335842-004 |publisher=DeGruyter|isbn=978-3-11-033584-2 }}

Siam's King Mongkut (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.{{efn|The Thai royal chronicles name the temple as Phathai Ta Phrom ({{lang|th|ผไทตาพรหม}}); some sources equate the name to the Ta Prohm temple known today.}} 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 built in the royal temple of Wat Phra Kaew in the Grand Palace instead.{{cite book |last1=Falser |first1=Michael |title=Angkor Wat – A Transcultural History of Heritage |volume=1 |chapter=Epilogue to Volume 1: Back to Asia: From Bangkok 1860 to Bihar 2020 |publisher= De Gruyter |date=2020 |pages=409–415 |doi=10.1515/9783110335842-013 |isbn=9783110335842}}

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.{{cite book |last=Edwards |first=Penny |title=Cambodge: The Cultivation of a Nation, 1860–1945 |chapter=1. The Temple Complex: Angkor and the Archaeology of Colonial Fantasy, 1860–1906 |date=2007 |pages=22, 29–31 |doi=10.1515/9780824861759-003 |publisher=University of Hawaii Press |isbn=9780824861759}}{{cite thesis|chapter=Chapter Three: Early Explorers |title="Discovering" Cambodia: Views of Angkor in French Colonial Cambodia (1863–1954) |type=PhD dissertation |publisher=Cornell University |first=Jennifer Lee |last=Foley |date=January 2006 |pages=75–76 |url=https://ecommons.cornell.edu/server/api/core/bitstreams/0b31843c-1ee3-49c5-90a9-863dce363515/content}}{{cite book |last1=Falser |first1=Michael |editor1-last=Falser |editor1-first=Michael |title=Cultural Heritage as Civilizing Mission |chapter=Epilogue: Clearing the Path towards Civilization – 150 Years of “Saving Angkor” |series=Transcultural Research – Heidelberg Studies on Asia and Europe in a Global Context |date=2015 |pages=279–346 |doi=10.1007/978-3-319-13638-7_12 |isbn=978-3-319-13638-7 |publisher=Springer}}

As colonial pressure increased towards the end of the century, King Chulalongkorn (Rama V) implemented centralizing reforms and introduced the Monthon Thesaphiban administration system to bring Siam's fringe towns and cities (mueang) 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{{efn|{{lang|th|พนมศก}}}} (Phnom Srok), was established as Monthon Khamen{{efn|{{lang|th|มณฑลเขมร}} 'Monthon Khmer'}} in 1891. Phraya Maha-ammattayathibbodi (Run Siphen) was posted as commissioner to the new monthon, based in Si Sophon.{{cite book |author1=สุพัฒศรี วรสายัณห์ |editor1-last=วุฒิชัย มูลศิลป์ |editor2-last=สมโชติ อ๋องสกุล |title=มณฑลเทศาภิบาล : วิเคราะห์เปรียบเทียบ |date=1981 |publisher=Social Science Association of Thailand |location=Bangkok |pages=203–264 |url=https://dl.parliament.go.th/bitstream/handle/lirt/371968/2524_%E0%B8%A1%E0%B8%93%E0%B8%91%E0%B8%A5%E0%B9%80%E0%B8%97%E0%B8%A8%E0%B8%A0%E0%B8%B4%E0%B8%9A%E0%B8%B2%E0%B8%A5_%E0%B8%A7%E0%B8%B8%E0%B8%92%E0%B8%B4%E0%B8%8A%E0%B8%B1%E0%B8%A2.pdf |archive-url=https://web.archive.org/web/20210716173515/https://dl.parliament.go.th/bitstream/handle/lirt/371968/2524_%E0%B8%A1%E0%B8%93%E0%B8%91%E0%B8%A5%E0%B9%80%E0%B8%97%E0%B8%A8%E0%B8%A0%E0%B8%B4%E0%B8%9A%E0%B8%B2%E0%B8%A5_%E0%B8%A7%E0%B8%B8%E0%B8%92%E0%B8%B4%E0%B8%8A%E0%B8%B1%E0%B8%A2.pdf |archive-date=2021-07-16 |language=th |chapter=การปกครองแบบเทศาภิบาล: มณฑลบูรพา}}

File:2016 Phnom Penh, Pomnik króla Sisowatha poświęcony traktatowi z 1907 roku (02).jpg.]]

However, the conflict with France soon erupted into the Franco-Siamese crisis of 1893, 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,{{cite web |title=ทัศนะการปกครองดินแดนเมืองพระตะบอง-มณฑลบูรพาช่วงสุดท้าย |url=https://www.silpa-mag.com/history/article_70187 |website=Silpa Wattanatham |language=th |date=11 March 2022}} which was renamed to Monthon Tawan-ok{{efn|{{lang|th|มณฑลตะวันออก}}}} 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 and Dan Sai, which had been under French occupation since 1904, as well as the ending of French extraterritoriality over Asian subjects.{{cite journal |last1=Briggs |first1=Lawrence Palmer |title=The Treaty of March 23, 1907 Between France and Siam and the Return of Battambang and Angkor to Cambodia |journal=The Far Eastern Quarterly |date=August 1946 |volume=5 |issue=4 |pages=439–454 |doi=10.2307/2049791|jstor=2049791 }} The last governor of Battambang under Siamese rule, {{ill|Chaophraya Aphaiphubet (Chum Abhayavongsa)|th|เจ้าพระยาอภัยภูเบศร (ชุ่ม อภัยวงศ์)|lt=Chum Abhayavongsa}}, 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.{{cite news |last1=Jariyasombat |first1=Peerawat |title=Tracing Prachin Buri's Khmer influence and history |url=https://www.bangkokpost.com/life/travel/1378575/tracing-prachin-buris-khmer-influence-and-history |access-date=23 February 2025 |work=Bangkok Post |date=14 December 2017 |language=en}}{{cite news |last1=Naiyuti |first1=Praepraphan |title=Reviving a shared history |url=https://www.bangkokpost.com/thailand/general/1532110/reviving-a-shared-history |access-date=23 February 2025 |work=Bangkok Post |date=1 September 2018 |language=en}}

File:Provinces of Cambodia loss to Thailand during Franco-Thai War.png in 1941]]

In the prelude to the Pacific theater of World War II, 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 and Laos' Champasak province (becoming Nakhon Champasak province) and Sainyabuli province (which became Lan Chang province).{{cite journal |last1=Landon |first1=Kenneth Perry |title=Thailand's Quarrel with France in Perspective |journal=The Far Eastern Quarterly |date=November 1941 |volume=1 |issue=1 |pages=25–42 |doi=10.2307/2049074|jstor=2049074 }}

Following Japan's defeat, Thailand relinquished these claims and returned the territories in 1946 as a condition for its admission into the United Nations.{{cite book |last1=Deth |first1=Sok Udom |title=A History of Cambodia-Thailand Diplomatic Relations 1950–2020 |date=2020 |publisher=Galda Verlag |location=Glienicke |isbn=9783962031305 |pages=18–20 |edition=Revised and updated version |url=https://books.google.com/books?id=WD0NEQAAQBAJ&pg=PA18}}

{{notelist}}

• Cambodia–Thailand relations

{{Reflist}}

Category:History of Cambodia

Category:History of Thailand

Category:Cambodia–Thailand relations

Category:Territorial evolution

Category:Former provinces of Thailand

Category:1907 disestablishments in Southeast Asia

Category:1795 establishments in Asia

Category:Annexation

{{Former provinces of Thailand}}