History of Cambodia

Radiocarbon dating of a cave at Laang Spean in Battambang Province, northwest Cambodia confirmed the presence of Hoabinhian stone tools from 6000–7000 BCE and pottery from 4200 BCE.^[1] Finds since 2012 lead to the common interpretation, that the cave contains the archaeological remains of a first occupation by hunter and gatherer groups, followed by Neolithic people with highly developed hunting strategies and stone tool making techniques, as well as highly artistic pottery making and design, and with elaborate social, cultural, symbolic and exequial practices.^[2] Cambodia participated in the Maritime Jade Road, which was in place in the region for 3,000 years, beginning in 2000 BCE to 1000 CE.^[3]

Skulls and human bones found at Samrong Sen in Kampong Chhnang Province date from 1500 BCE. Heng Sophady (2007) has drawn comparisons between Samrong Sen and the circular earthwork sites of eastern Cambodia. These people may have migrated from South-eastern China to the Indochinese Peninsula. Scholars trace the first cultivation of rice and the first bronze making in Southeast Asia to these people.

The Iron Age period of Southeast Asia begins around 500 BCE and lasts until the end of the Funan era - around 500 CE as it provides the first concrete evidence for sustained maritime trade and socio-political interaction with India and South Asia. By the 1st century settlers have developed complex, organised societies and a varied religious cosmology, that required advanced spoken languages very much related to those of the present day. The most advanced groups lived along the coast and in the lower Mekong River valley and the delta regions in houses on stilts where they cultivated rice, fished and kept domesticated animals.^[4]

Funan was the name given by Chinese cartographers, geographers and writers to an ancient Indianized state—or, rather a loose network of states (Mandala)^[5] — located in mainland Southeast Asia centered on the Mekong Delta that existed from the first to sixth century CE Chinese annals^[6] contain detailed records of the first known organised polity, the Kingdom of Funan, on Cambodian and Vietnamese territory characterised by "high population and urban centers, the production of surplus food...socio-political stratification [and] legitimized by Indian religious ideologies".^[7] Centered around the lower Mekong and Bassac rivers from the first to sixth century CE with "walled and moated cities"^[8] such as Angkor Borei in Takeo Province and Óc Eo in modern An Giang Province, Vietnam.

Early Funan was composed of loose communities, each with its own ruler, linked by a common culture and a shared economy of rice farming people in the hinterland and traders in the coastal towns, who were economically interdependent, as surplus rice production found its way to the ports.^[9]

By the second century CE Funan controlled the strategic coastline of Indochina and the maritime trade routes. Cultural and religious ideas reached Funan via the Indian Ocean trade route. Trade with India had commenced well before 500 BCE as Sanskrit hadn't yet replaced Pali.^[10] Funan's language has been determined as to have been an early form of Khmer and its written form was Sanskrit.^[11]

Funan reached the apex of its power under the 3rd-century king Fan Shiman. Fan Shiman expanded his empire's navy and improved the Funanese bureaucracy, creating a quasi-feudal pattern that left local customs and identities largely intact, particularly in the empire's further reaches. Fan Shiman and his successors also sent ambassadors to China and India to regulate sea trade. The kingdom likely accelerated the process of Indianization of Southeast Asia. Later kingdoms of Southeast Asia such as Chenla may have emulated the Funanese court. The Funanese established a strong system of mercantilism and commercial monopolies that would become a pattern for empires in the region.^[12]

Funan's dependence on maritime trade is seen as a cause for the beginning of Funan's downfall. Their coastal ports allowed trade with foreign regions that funnelled goods to the north and coastal populations. However, the shift in maritime trade to Sumatra, the rise in the Srivijaya trade empire, and the taking of trade routes all throughout Southeast Asia by China, leads to economic instability in the south, and forces politics and economy northward.^[12]

Funan was superseded and absorbed in the 6th century by the Khmer polity of the Chenla Kingdom (Zhenla).^[13] "The king had his capital in the city of T'e-mu. Suddenly his city was subjugated by Chenla, and he had to migrate south to the city of Nafuna".^[14]

Chenla is the Chinese designation for the successor polity of the kingdom of Funan preceding the Khmer Empire that existed from around the late sixth to the early ninth century in Indochina. Most of the Chinese recordings on Chenla, including that of Chenla conquering Funan have been contested since the 1970s as they are generally based on single remarks in the Chinese annals.^[15] The History of the Chinese Sui dynasty contains entries of a state called Chenla, a vassal of the Kingdom of Funan, which had sent an embassy to China in 616 or 617,^[16] yet under its ruler, Citrasena Mahendravarman, conquered Funan after Chenla had gained independence.^[17]

Like its predecessor Funan, Chenla occupied a strategic position where the maritime trade routes of the Indosphere and the East Asian cultural sphere converged, resulting in prolonged socio-economic and cultural influence and the adoption of the epigraphic system of the south Indian Pallava dynasty and Chalukya dynasty.^[18] The number of inscriptions declined sharply during the eighth century. However, some theorists, who have examined the Chinese transcripts, claim that Chenla started falling during the 700s as a result of both internal divisions and external attacks by the Shailendra dynasty of Java, who eventually took over and joined under the Angkor kingdom of Jayavarman II. Individually, historians reject a classical decline scenario, arguing there was no Chenla to begin with, rather a geographic region had been subject to prolonged periods of contested rule, with turbulent successions and an obvious incapability to establish a lasting centre of gravity. Historiography ends this era of nameless upheaval only in the year 802, when Jayavarman II established the appropriately named Khmer Empire.

The six centuries of the Khmer Empire are characterised by unparalleled technical and artistic progress and achievements, political integrity and administrative stability. The empire represents the cultural and technical apogee of the Cambodian and Southeast Asian pre-industrial civilisation.^[19] The Khmer Empire was preceded by Chenla, a polity with shifting centres of power, which was split into Land Chenla and Water Chenla in the early 8th century.^[20] By the late 8th century Water Chenla was absorbed by the Malays of the Srivijaya Empire and the Javanese of the Shailandra Empire and eventually incorporated into Java and Srivijaya.^[21]

Jayavarman II, is widely regarded as the king who set the foundations of the Angkor period. Historians generally agree that this period of Cambodian history began in 802, when Jayavarman II conducted a grandiose consecration ritual on the sacred Mount Mahendraparvata, now known as Phnom Kulen.^[22] In the following years, he extended his territory and established a new capital, Hariharalaya, near the modern-day town of Roluos.^[23] He thereby laid the foundation of Angkor, which was to arise some 15 kilometres (9.3 mi) to the northwest. The successors of Jayavarman II kept extending the territory of Kambuja. Indravarman I (reigned 877–889) managed to expand the kingdom without wars and initiated extensive building projects, which were enabled by the wealth gained through trade and agriculture. Foremost were the temple of Preah Ko and irrigation works. The water management network depended on elaborate configurations of channels, ponds, and embankments built from huge quantities of clayey sand, the available bulk material on the Angkor plain. Indravarman I developed Hariharalaya further by constructing Bakong circa 881. Bakong in particular bears striking similarities to the Borobudur temple in Java, which suggests that it may have served as the prototype for Bakong. There may have been exchanges of travellers and missions between Kambuja and the Sailendras in Java, which would have brought to Cambodia not only ideas, but also technical and architectural details.^[24]

The son of Rajendravarman II, Jayavarman V, reigned from 968 to 1001, after establishing himself as the new king over the other princes. His rule was a largely peaceful period, marked by prosperity and a cultural flowering. He established a new capital slightly west of his father's and named it Jayendranagari; its state temple, Ta Keo, was to the south. At the court of Jayavarman V lived philosophers, scholars, and artists. New temples were also established; the most important of these were Banteay Srei, considered one of the most beautiful and artistic of Angkor, and Ta Keo, the first temple of Angkor built completely of sandstone. Even though Jayavarman V was a Shaivite, he was very tolerant of Buddhism. And under his reign Buddhism flourished. Kirtipandita, his Buddhist minister, brought ancient texts from foreign lands to Cambodia, though none survived. He even suggested that priests used Buddhist prayers as well as Hindu during a ritual.

A decade of conflict followed the death of Jayavarman V. Three kings reigned simultaneously as antagonists to each other until Suryavarman I (reigned 1006–1050) ascended to the throne by taking the capital Angkor.^[24] His rule was marked by repeated attempts by his opponents to overthrow him and military conflicts with neighbouring kingdoms.^[26] Suryavarman I established diplomatic relations with the Chola dynasty of south India early in his rule.^[27] In the first decade of the 11th century, Kambuja came into conflict with the kingdom of Tambralinga in the Malay peninsula.^[26] After surviving several invasions from his enemies, Suryavarman requested aid from the powerful Chola emperor Rajendra I against Tambralinga.^[26] After learning of Suryavarman's alliance with Chola, Tambralinga requested aid from the Srivijaya king Sangrama Vijayatungavarman.^[26] This eventually led to Chola coming into conflict with Srivijaya. The war ended with a victory for Chola and Kambuja, and major losses for Srivijaya and Tambralinga.^[26] The two alliances had religious nuance, as Chola and Kambuja were Hindu Shaivite, while Tambralinga and Srivijaya were Mahayana Buddhist. There is some indication that, before or after the war, Suryavarman I gifted a chariot to Rajendra I to possibly facilitate trade or an alliance.^[24]

In 1074, Harivarman IV became king of Champa. He had close ties to Song China and made peace with Dai Viet, but provoked a war with the Khmer Empire.^[28] In 1080, a Khmer army attacked Vijaya and other centers in northern Champa. Temples and monasteries were sacked and cultural treasures were carried off. After much chaos, Cham troops under King Harivarman were able to defeat the invaders and restore the capital and temples.^[29] Subsequently, his raiding forces penetrated Cambodia as far as Sambor and the Mekong, where they destroyed all religious sanctuaries.^[30]

The 12th century was a time of conflict and brutal power struggles. Under Suryavarman II (reigned 1113–1150) the kingdom united internally^[31] and the empire reached its greatest geographic extent as it directly or indirectly controlled Indochina, the Gulf of Thailand and large areas of northern maritime Southeast Asia. Suryavarman II commissioned the temple of Angkor Wat, built in a period of 37 years, which was dedicated to the god Vishnu. Its five towers representing Mount Meru is considered to be the most accomplished expression of classical Khmer architecture. In the east, Suryavarman II's campaigns against Champa and Dai Viet were unsuccessful,^[31]  though he sacked Vijaya in 1145 and deposed Jaya Indravarman III.^[32] The Khmers occupied Vijaya until 1149, when they were driven out by Jaya Harivarman I.^[33 ] However, territorial expansion ended when Suryavarman II was killed in battle attempting to invade Đại Việt. It was followed by a period of dynastic upheaval and a Cham invasion that culminated in the sack of Angkor in 1177.

In 1127, Suryavarman II demanded Đại Việt king Lý Dương Hoán to pay tribute for the Khmer Empire, but the Đại Việt refused. Suryavarman decided to expand his territory northward into Đại Việt territory.^[34] The first attack was in 1128 when King Suryavarman led 20,000 soldiers from Savannakhet to Nghệ An, where they were routed in battle.^[35] The following year Suryavarman continued skirmishes on land and sent 700 ships to bombard the coastal areas of Đại Việt. In 1132, he persuaded Cham king Jaya Indravarman III to join forces with him to attack Đại Việt, where they briefly seized Nghệ An and pillaged the coastal districts of Thanh Hoá.^[36] In 1136, a Đại Việt force under Đỗ Anh Vũ counterattacked the Khmer Empire across modern-day Laos with 30,000 men, but later retreated.^[34] The Cham thereupon made peace with the Đại Việt, and when Suryavarman renewed the attack, Jaya Indravarman refused to cooperate with the Khmers.^[36]

After a failed attempt to seize seaports in southern Đại Việt, Suryavarman turned to invade Champa in 1145 and sacked Vijaya, ending the reign of Jaya Indravarman III and destroying the temples at Mỹ Sơn.^[37] In 1147 when a Panduranga prince named Sivänandana was enthroned as Jaya Harivarman I of Champa, Suryavarman sent an army consisting of Khmers and defected Chams under the command of the senäpati (military commander) Sankara to attack Harivarman, but was defeated in the battle of Räjapura in 1148. Another stronger Khmer army also suffered the same wretchedness fate at the battles of Virapura (present-day Nha Trang) and Caklyaṅ. Unable to overwhelm the Cham, Suryavarman appointed Prince Harideva, a Cham royalty of Cambodian background, as the puppet king of Champa in Vijaya. In 1149, Harivarman marched his army northward to Vijaya, besieging the city, vanquishing Harideva's army at the battle of Mahisa, then executed Harideva along with all of his Cambodian–Cham officials and military, therefore ended Suryavarman's occupation of northern Champa.^[37] Harivarman then reunited the kingdom.

After securing peace with Đại Việt in 1170, Cham forces under Jaya Indravarman IV invaded the Khmer Empire over land with inconclusive results.^[38] That year, a Chinese official from Hainan had witnessed elephant duel battles between Cham and Khmer armies, henceforth convincing the Cham king to offer war horse purchases from China, but the offer was rejected by the Song court multiple times. In 1177, however, his troops launched a surprise attack against the Khmer capital of Yasodharapura from warships ploted up the Mekong River to the great lake Tonlé Sap and killed the Khmer king Tribhuvanadityavarman.^[39] Multiple-bow siege crossbows were introduced to Champa from Song dynasty in 1171, and later were mounted on the backs of Cham and Vietnamese war elephants.^[40] They were deployed by the Cham during the siege of Angkor, which was lightly defended by wooden palisades, leading to the Cham occupation of Cambodia for the next four years.^[40]

The Khmer empire was in the verge of collapse. After Champa had conquered Angkor, Jayavarman VII gathered an army and retook the capital. His army won a series of unprecedented victories over the Cham, and by 1181 after winning a decisive naval battle, Jayavarman had rescued the empire and expelled the Cham. He consequently ascended to the throne and continued to wage war against Champa for another 22 years, until the Khmer defeated the Chams in 1203 and conquered large parts of their territory.^[41]

Jayavarman VII stands as the last of the great kings of Angkor, not only because of his successful military campaign against Champa, but also because he was not a tyrannical ruler in the manner of his immediate predecessors. He unified the empire and carried out noteworthy building projects. The new capital, now called Angkor Thom (lit. 'great city'), was built. In the centre, the king (himself a follower of Mahayana Buddhism) had constructed as the state temple the Bayon,^[42]  with towers bearing faces of the boddhisattva Avalokiteshvara, each several metres high, carved out of stone. Further important temples built under Jayavarman VII were Ta Prohm for his mother, Preah Khan for his father, Banteay Kdei, and Neak Pean, as well as the reservoir of Srah Srang. An extensive network of roads was laid down connecting every town of the empire, with rest-houses built for travellers and a total of 102 hospitals established across his realm.^[41]

In 1190, the Khmer king Jayavarman VII appointed a Cham prince named Vidyanandana, who had defected to Jayavarman in 1182 and had been educated at Angkor, to lead the Khmer army. Vidyanandana defeated the Chams, and proceeded to occupy Vijaya and captured Jaya Indravarman IV, whom he sent back to Angkor as a prisoner.^[43] Adopting the title of Shri Suryavarmadeva (or Suryavarman), Vidyanandana made himself king of Panduranga, which became a Khmer vassal. He made Prince In, a brother-in-law of Jayavarman VII, "King Suryajayavarmadeva in the Nagara of Vijaya" (or Suryajayavarman). In 1191, a revolt at Vijaya drove Suryajayavarman back to Cambodia and enthroned Jaya Indravarman V. Vidyanandana, assisted by Jayavarman VII, retook Vijaya, killing both Jaya Indravarman IV and Jaya Indravarman V, then "reigned without opposition over the Kingdom of Champa,"^[44] declaring his independence from the Khmer Empire. Jayavarman VII responded by launching several invasions of Champa in 1192, 1195, 1198–1199, 1201-1203. Khmer armies under Jayavarman VII continued campaigning against Champa until the Chams were finally defeated in 1203.^[45] A Cham renegade-Prince ong Dhanapatigräma, overthrew and expelled his ruling nephew Vidyanandana to Dai Viet, completing the Khmer conquest of Champa.^[46] From 1203 to 1220, Champa as a Khmer province was ruled by a puppet government led by either ong Dhanapatigräma and then prince Angsaräja, son of Harivarman I. In 1207, Angsaräja accompanied a Khmer army with Burmese and Siamese mercenacy contingents to battle against the Yvan (Dai Viet) army.^[47] Following the dwindling Khmer military presence and voluntary Khmer evacuation of Champa in 1220, Angsaräja took over the reins of government peacefully, proclaiming himself Jaya Paramesvaravarman II, and restored Champa's independence.^[48]

After the death of Jayavarman VII, his son Indravarman II (reigned 1219–1243) ascended to the throne. Jayavarman VIII was one of the prominent kings of the Khmer empire. Like his father, he was a Buddhist, and he completed a series of temples begun under his father's rule. As a warrior he was less successful. In 1220, under mounting pressure from the increasingly powerful Dai Viet and its ally Champa, the Khmer withdrew from many of the provinces previously conquered from the Chams.

Indravarman II was succeeded by Jayavarman VIII (reigned 1243–1295). In contrast to his predecessors, Jayavarman VIII was a follower of Hindu Shaivism and an aggressive opponent of Buddhism, destroying many Buddha statues in the empire and converting Buddhist temples to Hindu temples.^[49] Kambuja was threatened externally in 1283 by the Mongol-led Yuan dynasty.^[50] Jayavarman VIII avoided war with general Sogetu, the governor of Guangzhou, China, by paying annual tribute to the Mongols, starting in 1285.^[51 ] Jayavarman VIII's rule ended in 1295 when he was deposed by his son-in-law Srindravarman (reigned 1295–1309). The new king was a follower of Theravada Buddhism, a school of Buddhism that had arrived in southeast Asia from Sri Lanka and subsequently spread through most of the region. In August 1296, the Chinese diplomat Zhou Daguan arrived in Angkor and recorded, "In the recent war with the Siamese, the country was utterly devastated".^[52]

By the 14th century, the Khmer Empire or Kambuja had suffered a long, arduous, and steady decline. Historians have proposed different causes for the decline: the religious conversion from Vishnuite-Shivaite Hinduism to Theravada Buddhism that affected social and political systems, incessant internal power struggles among Khmer princes, vassal revolt, foreign invasion, plague, and ecological breakdown. For social and religious reasons, many aspects contributed to the decline of Kambuja. The relationship between the rulers and their elites was unstable – among the 27 rulers of Kambuja, eleven lacked a legitimate claim to power, and violent power struggles were frequent. Kambuja focused more on its domestic economy and did not take advantage of the international maritime trade network. The input of Buddhist ideas also conflicted with and disturbed the state order built under Hinduism.^[53]

The Ayutthaya Kingdom arose from a confederation of three city-states on the Lower Chao Phraya basin (Ayutthaya-Suphanburi-Lopburi).^[54] From the fourteenth century onward, Ayutthaya became Kambuja's rival.^[55] Angkor was besieged by the Ayutthayan King Uthong in 1352, and following its capture the next year, the Khmer king was replaced with successive Siamese princes. Then in 1357, the Khmer king Suryavamsa Rajadhiraja retook the throne.^[56]  In 1393, the Ayutthayan king Ramesuan besieged Angkor again, capturing it the next year. Ramesuan's son ruled Kambuja for a short time before being assassinated. Finally, in 1431, the Khmer king Ponhea Yat abandoned Angkor as indefensible, and moved to the Phnom Penh area.^[57]

Phnom Penh first became the capital of Cambodia after Ponhea Yat, king of the Khmer Empire, moved the capital from Angkor Thom after it was captured and destroyed by Siam a few years earlier. Phnom Penh remained the royal capital for 73 years, from 1432 to 1505. In Phnom Penh, the king ordered the land to be built up to protect it from flooding, and a palace to be built. Thus, it controlled the river commerce of the Khmer heartland, upper Siam and the Laotian kingdoms with access, by way of the Mekong Delta, to the international trade routes that linked the Chinese coast, the South China Sea, and the Indian Ocean. Unlike its inland predecessor, this society was more open to the outside world and relied mainly on commerce as the source of wealth. The adoption of maritime trade with China during the Ming dynasty (1368–1644) provided lucrative opportunities for members of the Cambodian elite who controlled royal trading monopolies.

Messengers of Portuguese admiral Alfonso de Albuquerque, conqueror of Malacca arrived in Indochina in 1511, the earliest documented official contact with European sailors. By the late sixteenth and early seventeenth centuries, Longvek maintained flourishing communities of Chinese, Indonesians, Malays, Japanese, Arabs, Spaniards, English, Dutch and Portuguese traders.^[58]

King Ang Chan I (1516–1566) moved the capital from Phnom Penh north to Longvek at the banks of the Tonle Sap river. Trade was an essential feature and "...even though they appeared to have a secondary role in the Asian commercial sphere in the 16th century, the Cambodian ports did indeed thrive." Products traded there included precious stones, metals, silk, cotton, incense, ivory, lacquer, livestock (including elephants), and rhinoceros horn.

Cambodia was attacked by the Ayutthaya Kingdom led by Thai prince and warlord Naresuan in 1583.^[59] The war began in 1591 when Ayutthaya invaded Cambodia in response to continuous Khmer raids into their territory. The Kingdom of Cambodia was also facing religious disagreements within the country. This gave the Siamese a perfect opportunity to invade. Longvek was captured in 1594 which marked the beginning of the establishment of a Siamese military governor in the city. For the first time a degree of foreign political control was established over the kingdom as the seat of the sovereign was demoted to that of a vassal.^[60] Following the Siam capture of the capital at Longvek, Cambodian royals were taken hostage and relocated at the court of Ayutthaya, kept under permanent Thai influence and left to compromise and out-compete each other under the overlord's scrutiny.^[61]

In February 1593, Thai ruler Naresuan attacked Cambodia.^[62] Later on, in May 1593, 100,000 Thai (Siamese) soldiers invaded Cambodia.^[63] The increasing Siamese expansion, which later got the approval of China, drove the Cambodian king Satha I to search for allies overseas, ultimately finding it in Portuguese adventurer Diogo Veloso and his Spanish associates Blas Ruiz de Hernán Gonzáles and Gregorio Vargas Machuca.^[64] The Cambodian–Spanish War was an attempt to conquer Cambodia on behalf of King Satha I and Christianize Cambodia's population by the Spanish and Portuguese Empires.^[65] Along with the Spanish, Spanish Filipinos, native Filipinos, Mexican recruits, and Japanese mercenaries participated in the invasion of Cambodia.^[66] Because of its defeat, Spain's planned Christianization of Cambodia failed.^[67] Laksamana later had Barom Reachea II executed. Cambodia became dominated by the Thai in July 1599.^[68]

The Kingdom of Cambodia is centered at the Mekong, prospering as an integral part of the Asian maritime trade network,^[69] via which the first contact with European explorers and adventurers does occur.^[70] By the 17th century Siam and Vietnam increasingly fought over control of the fertile Mekong basin, enhancing pressure on weakened Cambodia. This marks the beginning of direct relations between post-Angkor Cambodia and Vietnam. The Vietnamese on their "Southward March" reach Prei Nokor/Saigon at the Mekong Delta in the 17th century. This event initiates the slow process of Cambodia losing access to the seas and independent marine trade.^[71]

Siamese and Vietnamese dominance intensified during the 17th and 18th century, resulting in frequent displacements of the seat of power as the Khmer royal authority decreased to the state of a vassal. Siam, which might otherwise have been courted as an ally against Vietnamese incursions in the 18th century, was itself involved in prolonged conflicts with Burma and in 1767 the Siamese capital of Ayutthaya was completely destroyed. However, Siam recovered and soon reasserted its dominion over Cambodia. The youthful Khmer king Ang Eng (1779–96) was installed as monarch at Oudong while Siam annexed Cambodia's Battambang and Siem Reap provinces. The local rulers became vassals under direct Siamese rule.^[72]

Siam and Vietnam had fundamentally different attitudes concerning their relationship with Cambodia. The Siamese shared a common religion, mythology, literature, and culture with the Khmer, having adopted many religious and cultural practices.^[73] The Thai Chakri kings followed the Chakravatin system of an ideal universal ruler, ethically and benevolently ruling over all his subjects. The Vietnamese enacted a civilising mission, as they viewed the Khmer people as culturally inferior and regarded the Khmer lands as legitimate site for colonisation by settlers from Vietnam.^[74]

A renewed struggle between Siam and Vietnam for control of Cambodia and the Mekong basin in the early 19th century resulted in Vietnamese dominance over a Cambodian vassal king. Attempts to force Cambodians to adopt Vietnamese customs caused several rebellions against Vietnamese rule. The most notable took place from 1840 to 1841, spreading through much of the country. The territory of the Mekong Delta became a territorial dispute between Cambodians and Vietnamese. Cambodia gradually lost control of the Mekong Delta.

The Vietnamese invasions of Cambodia refers to the period of Cambodian history, between 1813 and 1845, when the Kingdom of Cambodia was invaded by the Vietnamese Nguyễn dynasty three times, and a brief period from 1834 to 1841 when Cambodia was part of Tây Thành province in Vietnam, undertaken by Vietnamese emperors Gia Long (r. 1802–1819) and Minh Mạng (r. 1820–1841). The first invasion that took place in 1811–1813 put Cambodia as Vietnam's client kingdom. The second invasion in 1833–1834 made Cambodia a de facto Vietnamese province. Minh Mạng's harsh rule of the Cambodians finally ended after he died in early 1841, an event which coincided with a Cambodian rebellion, and both which triggered a Siamese intervention in 1842. The unsuccessful third invasion of 1845 resulted in the independence of Cambodia. Siam and Vietnam signed a peace treaty in 1847, allowing Cambodia to reassert its independence in 1848.

In 1840, the Cambodian queen Ang Mey was deposed by Vietnamese; she was arrested and deported to Vietnam along with her relatives and the royal regalia. Spurred by the incident, many Cambodian courtiers and their followers revolted against the Vietnamese rule.^[75] The rebels appealed to Siam who supported another claimant to the Cambodian throne, Prince Ang Duong. Rama III responded and sent Ang Duong back from exile in Bangkok with Siamese troops to install him on the throne.^[76]

The Vietnamese suffered attack from both Siamese troops and Cambodian rebels. What was worse, in Cochinchina, there were several rebellion broke out. The main strength of Vietnamese marched to Cochinchina to put down those rebellions. Thiệu Trị, the new crowned Vietnamese emperor, decided to seek a peaceful resolution.^[77] Trương Minh Giảng, the Governor-General of Trấn Tây (Cambodia), was called back. Giảng was arrested and later committed suicide in prison.^[78]

Ang Duong agreed to place Cambodia under joint Siamese-Vietnamese protection in 1846. The Vietnamese released Cambodian royalties and returned the royal regalia. In the same time, Vietnamese troops pulled out of Cambodia. Finally, Vietnamese lost control of this country, Cambodia won independence from Vietnam. Though there were still a few Siamese troops stayed in Cambodia, the Cambodian king had greater autonomy than before.^[79]

In the early 19th century with dynasties in Vietnam and Siam firmly established, Cambodia was placed under joint suzerainty, having lost its national sovereignty. British agent John Crawfurd states: "...the King of that ancient Kingdom is ready to throw himself under the protection of any European nation..." To save Cambodia from being incorporated into Vietnam and Siam, the Cambodians entreated the aid of the Luzones/Lucoes (Filipinos from Luzon-Philippines) that previously participated in the Burmese-Siamese wars as mercenaries. When the embassy arrived in Luzon, the rulers were now Spaniards, so they asked them for aid too, together with their Latin American troops imported from Mexico, in order to restore the then Christianised King, Satha II, as monarch of Cambodia, this, after a Thai/Siamese invasion was repelled. However that was only temporary. Nevertheless, the future King, Ang Duong, also enlisted the aid of the French who were allied to the Spanish (As Spain was ruled by a French royal dynasty the Bourbons). The Cambodian king agreed to colonial France's offers of protection in order to restore the existence of the Cambodian monarchy, which took effect with King Norodom Prohmbarirak signing and officially recognising the French protectorate on 11 August 1863. By the 1860s French colonist had taken over the Mekong Delta and establish the colony of French Cochinchina.

The first decades of French rule in Cambodia included numerous reforms into Cambodian politics, such as the reduction of the monarch's power and abolition of slavery. In 1884, the governor of Cochinchina, Charles Antoine François Thomson, attempted to overthrow the monarch and establish full French control over Cambodia by sending a small force to the royal palace in Phnom Penh. The movement was only slightly successful as the governor-general of French Indochina prevented full colonisation due to possible conflicts with Cambodians and the monarch's power was reduced to that of a figurehead.^[80]

In 18880, Si Votha, half brother of Norodom and contender for the throne, led a rebellion to dispose of the French-backed Norodom after coming back from exile in Siam. Gathering support from opposers of Norodom and the French, Si Votha led a rebellion that was primarily concentrated in the jungles of Cambodia and the city of Kampot where Oknha Kralahom "Kong" led the resistance. French forces later aided Norodom to defeat Si Votha under agreements that the Cambodian population be disarmed and acknowledge the resident-general as the highest power in the protectorate.^[80] Oknha Kralahom "Kong" was called back to Phnom Penh to discuss peace with King Norodom and the French officials, but was taken captive by the French army and subsequently killed, officially putting an end to the rebellion.

In 1896, France and the British Empire signed an accord recognizing each other's sphere of influence over Indochina, especially over Siam. Under this accord, Siam had to cede the province of Battambang back to the now French-controlled Cambodia. The accord acknowledged French control over Vietnam (including the colony of Cochinchina and the protectorates of Annam and Tonkin), Cambodia, as well as Laos, which was added in 1893 following French victory in the Franco-Siamese War and French influence over eastern Siam. The French government also later placed new administrative posts in the colony and began to develop it economically while introducing French culture and language to locals as part of an assimilation program.^[81]

In 1897, the ruling Resident-General complained to Paris that the current king of Cambodia, King Norodom was no longer fit to rule and asked for permission to assume the king's powers to collect taxes, issue decrees, and even appoint royal officials and choose crown princes. From that time, Norodom and the future kings of Cambodia were figureheads and merely were patrons of the Buddhist religion in Cambodia, though they were still viewed as god-kings by the peasant population. All other power was in the hands of the Resident-General and the colonial bureaucracy. This bureaucracy was formed mostly of French officials, and the only Asians freely permitted to participate in government were ethnic Vietnamese, who were viewed as the dominant Asians in the Indochinese Union.

After the Fall of France in 1940, Cambodia and the rest of French Indochina were ruled by the Axis-puppet Vichy France government and despite an invasion of French Indochina, Japan allowed French colonial officials to remain in their colonies under Japanese supervision. In December 1940, the French-Thai War erupted and despite French resistance against the Japanese backed Thai forces, Japan compelled French authorities to cede Battambang, Sisophon, Siem Reap (excluding Siem Reap town) and Preah Vihear provinces to Thailand.^[82]

The subject of European colonies in Asia was among those discussed during the war by the Allied leaders of the Big Three , Franklin D. Roosevelt, Stalin, and Churchill at the three summit meetings - Cairo Conference, Tehran Conference and Yalta Conference. In regards to non-British colonies in Asia, Roosevelt and Stalin had decided in Tehran that the French and the Dutch would not return to Asia after the war. Roosevelt's untimely death before the war's end, was followed by developments very different from what Roosevelt had envisaged. The British backed the return of French and Dutch rule in Asia and organised dispatches of Indian soldiers under British command for this purpose.^[83]

In an effort to enlist local support in the final months of the war, the Japanese dissolved the French colonial administration on 9 March 1945, and urged Cambodia to declare its independence within the Greater East Asia Co-Prosperity Sphere. Four days later, King Sihanouk decreed an independent Kampuchea (the original Khmer pronunciation of Cambodia). On 15 August 1945, the day Japan surrendered, a new government was established with Son Ngoc Thanh acting as prime minister. When an Allied force occupied Phnom Penh in October, Thanh was arrested for collaboration with the Japanese and was sent into exile in France to remain under house arrest.

The Kingdom of Cambodia, also known as the First Kingdom of Cambodia, and commonly referred to as the Sangkum period, refers to Norodom Sihanouk's first administration of Cambodia from 1953 to 1970, an especially significant time in the country's history. Sihanouk continues to be one of the most controversial figures in Southeast Asia's turbulent and often tragic postwar history. From 1955 until 1970, Sihanouk's Sangkum was the sole legal party in Cambodia.^[84]

Following the end of World War II, France restored its colonial control over Indochina but faced local resistance against their rule, particularly from Communist guerilla forces. On 9 November 1953 it would achieve independence from France under Norodom Sihanouk but still faced resistance from Communist groups such as United Issarak Front. As the Vietnam War escalated, Cambodia sought to remain its neutrality but in 1965, North Vietnamese soldiers were allowed to set bases up and in 1969, the United States began a bombing campaign against North Vietnamese soldiers in Cambodia. The Cambodian monarchy would be abolished in a US-backed coup on October 9, 1970 headed by Prime Minister Lon Nol who established the Khmer Republic which lasted until the fall of Phnom Penh in 1975.^[85]

The Cambodian Civil War was a civil war in Cambodia fought between the forces of the Communist Party of Kampuchea (known as the Khmer Rouge, supported by North Vietnam and the Viet Cong) against the government forces of the Kingdom of Cambodia and, after October 1970, the Khmer Republic, which had succeeded the kingdom (both supported by the United States and South Vietnam).

The struggle was complicated by the influence and actions of the allies of the two warring sides. North Vietnam's People's Army of Vietnam (PAVN) involvement was designed to protect its Base Areas and sanctuaries in eastern Cambodia, without which it would have been harder to pursue its military effort in South Vietnam. Their presence was at first tolerated by Prince Sihanouk, the Cambodian head of state, but domestic resistance combined with China and North Vietnam continuing to provide aid to the anti-government Khmer Rouge alarmed Sihanouk and caused him to go to Moscow to request the Soviets rein in the behavior of North Vietnam.^[86] The deposition of Sihanouk by the Cambodian National Assembly in March 1970, following wide scale protests in the capital against the presence of PAVN troops in the country, put a pro-American government in power (later declared the Khmer Republic) which demanded that the PAVN leave Cambodia. The PAVN refused and, at the request of the Khmer Rouge, promptly invaded Cambodia in force.

Between March and June 1970, the North Vietnamese captured most of the northeastern third of the country in engagements with the Cambodian army. The North Vietnamese turned over some of their conquests and provided other assistance to the Khmer Rouge, thus empowering what was at the time a small guerrilla movement.^[87] The Cambodian government hastened to expand its army to combat the North Vietnamese and the growing power of the Khmer Rouge.^[88]

The U.S. was motivated by the desire to buy time for its withdrawal from Southeast Asia, to protect its ally in South Vietnam, and to prevent the spread of communism to Cambodia. American and both South and North Vietnamese forces directly participated (at one time or another) in the fighting. The U.S. assisted the central government with massive U.S. aerial bombing campaigns and direct material and financial aid, while the North Vietnamese kept soldiers on the lands that they had previously occupied and occasionally engaged the Khmer Republic army in ground combat.

After five years of savage fighting, the Republican government was defeated on 17 April 1975 when the victorious Khmer Rouge proclaimed the establishment of Democratic Kampuchea. The war caused a refugee crisis in Cambodia with two million people—more than 25 percent of the population—displaced from rural areas into the cities, especially Phnom Penh which grew from about 600,000 in 1970 to an estimated population of nearly 2 million by 1975.

Immediately after its victory, the CPK ordered the evacuation of all cities and towns, sending the entire urban population into the countryside to work as farmers, as the CPK was trying to reshape society into a model that Pol Pot had conceived. The new government sought to completely restructure Cambodian society. Remnants of the old society were abolished and religion was suppressed. Agriculture was collectivised, and the surviving part of the industrial base was abandoned or placed under state control. Cambodia had neither a currency nor a banking system.

Democratic Kampuchea's relations with Vietnam and Thailand worsened rapidly as a result of border clashes and ideological differences. While communist, the CPK was fiercely nationalistic, and most of its members who had lived in Vietnam were purged. Democratic Kampuchea established close ties with the People's Republic of China, and the Cambodian-Vietnamese conflict became part of the Sino-Soviet rivalry, with Moscow backing Vietnam. Border clashes worsened when the Democratic Kampuchea military attacked villages in Vietnam. The regime broke off relations with Hanoi in December 1977, protesting Vietnam's alleged attempt to create an Indochina Federation. In mid-1978, Vietnamese forces invaded Cambodia, advancing about 30 miles (48 km) before the arrival of the rainy season.

The reasons for Chinese support of the CPK was to prevent a pan-Indochina movement, and maintain Chinese military superiority in the region. The Soviet Union supported a strong Vietnam to maintain a second front against China in case of hostilities and to prevent further Chinese expansion. Since Stalin's death, relations between Mao-controlled China and the Soviet Union had been lukewarm at best. In February to March 1979, China and Vietnam would fight the brief Sino-Vietnamese War over the issue.

Within the CPK, the Paris-educated leadership—Pol Pot, Ieng Sary, Nuon Chea, and Son Sen — were in control. A new constitution in January 1976 established Democratic Kampuchea as a Communist People's Republic, and a 250-member Assembly of the Representatives of the People of Kampuchea (PRA) was selected in March to choose the collective leadership of a State Presidium, the chairman of which became the head of state. Prince Sihanouk resigned as head of state on 2 April and was put under virtual house arrest.

The Cambodian genocide was the systematic persecution and killing of Cambodian citizens by the Khmer Rouge under the leadership of Communist Party of Kampuchea general secretary Pol Pot. It resulted in the deaths of 1.5 to 2 million people from 1975 to 1979, nearly a quarter of Cambodia's population in 1975 (c. 7.8 million).^[89] The massacres ended when the Vietnamese military invaded in 1978 and toppled the Khmer Rouge regime. By January 1979, 1.5 to 2 million people had died due to the Khmer Rouge's policies, including 200,000–300,000 Chinese Cambodians, 90,000–500,000 Cambodian Cham (who are mostly Muslim),^[90] and 20,000 Vietnamese Cambodians.^[91] 20,000 people passed through the Security Prison 21, one of the 196 prisons the Khmer Rouge operated,^[92] and only seven adults survived.^[93] The prisoners were taken to the Killing Fields, where they were executed (often with pickaxes, to save bullets)^[94] and buried in mass graves. Abduction and indoctrination of children was widespread, and many were persuaded or forced to commit atrocities.^[95] As of 2009, the Documentation Center of Cambodia has mapped 23,745 mass graves containing approximately 1.3 million suspected victims of execution. Direct execution is believed to account for up to 60% of the genocide's death toll,^[96] with other victims succumbing to starvation, exhaustion, or disease. The genocide triggered a second outflow of refugees, many of whom escaped to neighboring Thailand and, to a lesser extent, Vietnam.^[97]

In 2001, the Cambodian government established the Khmer Rouge Tribunal to try the members of the Khmer Rouge leadership responsible for the Cambodian genocide. Trials began in 2009, and in 2014, Nuon Chea and Khieu Samphan were convicted and received life sentences for crimes against humanity committed during the genocide.

On 10 January 1979, after the Vietnamese army and the KUFNS (Kampuchean United Front for National Salvation) invaded Cambodia and overthrew the Khmer Rouge, the new People's Republic of Kampuchea (PRK) was established with Heng Samrin as head of state. Pol Pot's Khmer Rouge forces retreated rapidly to the jungles near the Thai border. The Khmer Rouge and the PRK began a costly struggle that played into the hands of the larger powers China, the United States and the Soviet Union. The Khmer People's Revolutionary Party's rule gave rise to a guerrilla movement of three major resistance groups – the FUNCINPEC (Front Uni National pour un Cambodge Indépendant, Neutre, Pacifique, et Coopératif), the KPLNF (Khmer People's National Liberation Front) and the PDK (Party of Democratic Kampuchea, the Khmer Rouge under the nominal presidency of Khieu Samphan).^[98] "All held dissenting perceptions concerning the purposes and modalities of Cambodia's future". Civil war displaced 600,000 Cambodians, who fled to refugee camps along the border to Thailand and tens of thousands of people were murdered throughout the country.^[99] Peace efforts began in Paris in 1989 under the State of Cambodia, culminating two years later in October 1991 in a comprehensive peace settlement. The United Nations was given a mandate to enforce a ceasefire and deal with refugees and disarmament known as the United Nations Transitional Authority in Cambodia (UNTAC).^[100]

After the fall of the Pol Pot regime of Democratic Kampuchea, Cambodia was under Vietnamese occupation and a pro-Hanoi government, the People's Republic of Kampuchea, was established. A civil war raged during the 1980s opposing the government's Kampuchean People's Revolutionary Armed Forces against the Coalition Government of Democratic Kampuchea, a government in exile composed of three Cambodian political factions: Prince Norodom Sihanouk's FUNCINPEC party, the Party of Democratic Kampuchea (often referred to as the Khmer Rouge) and the Khmer People's National Liberation Front (KPNLF).

Peace efforts intensified in 1989 and 1991 with two international conferences in Paris, and a United Nations peacekeeping mission helped maintain a ceasefire. As a part of the peace effort, United Nations-sponsored elections were held in 1993 and helped restore some semblance of normality, as did the rapid diminishment of the Khmer Rouge in the mid-1990s. Norodom Sihanouk was reinstated as King. A coalition government, formed after national elections in 1998, brought renewed political stability and the surrender of remaining Khmer Rouge forces in 1998.

Hun Sen and his government have seen much controversy. Hun Sen was a former Khmer Rouge commander who was originally installed by the Vietnamese and, after the Vietnamese left the country, maintains his strong man position by violence and oppression when deemed necessary.^[101] In 1997, fearing the growing power of his co-Prime Minister, Prince Norodom Ranariddh, Hun launched a coup, using the army to purge Ranariddh and his supporters. Ranariddh was ousted and fled to Paris while other opponents of Hun Sen were arrested, tortured and some summarily executed.^[101]

The Cambodia National Rescue Party was dissolved ahead of the 2018 Cambodian general election and the ruling Cambodian People's Party also enacted tighter curbs on mass media.^[102] The CPP won every seat in the National Assembly without a major opposition, effectively solidifying de facto one-party rule in the country.^[103]

Cambodia’s longtime Prime Minister Hun Sen, one of the world’s longest-serving leaders, has a very firm grip on power. He has been accused of the crackdown on opponents and critics. His Cambodian People’s Party (CPP) has been in power since 1979. In December 2021, Prime Minister Hun Sen announced his support for his son Hun Manet to succeed him after the next election, which is expected to take place in 2023.^[104]