The history of Cambodia

Cambodia is the heartland of the Khmer people, whose ancestors built the early trading state of Funan and then, from the ninth to the fifteenth century, the Khmer Empire, centred on Angkor, which for a time dominated mainland South-east Asia. After Angkor was abandoned, a smaller kingdom on the Mekong was squeezed between Siam and Vietnam until France made it a protectorate in 1863. Independent from 1953, Cambodia was drawn into the Vietnam War, and from 1975 to 1979 the Khmer Rouge regime of Pol Pot carried out a genocide in which around a quarter of the population died. Vietnamese occupation, civil war and a United Nations peace operation followed, and since the 1990s the country has rebuilt under a restored monarchy and the long rule of Hun Sen's Cambodian People's Party.

The cave of Laang Spean in Battambang province in the north-west holds a record of human occupation reaching back some 70,000 years, with Hoabinhian stone tools from about 7000 to 6000 BCE and pottery from around 4200 BCE. At Samrong Sen, on a tributary of the Tonle Sap, people living around 1500 BCE farmed, made pottery and later worked bronze. In the east, villages surrounded by circular earthworks appeared in the late prehistoric period, and by about 500 BCE iron was in use. Cemeteries such as Phum Snay in the north-west show a society of rice farmers with weapons, ornaments and, from many skeletons with head wounds, frequent violence. The great flood pulse of the Tonle Sap lake, which swells each wet season and empties back into the Mekong, provided abundant fish and fertile soils, and it would feed every later Cambodian state.

From the first century CE, Chinese records describe a state they called Funan on the lower Mekong and the coasts of the Gulf of Thailand. Its walled and moated towns included Angkor Borei in today's Takeo province and the port of Oc Eo, now in southern Vietnam, where Roman coins, Indian beads and Chinese bronzes have been found. Funan lay on the sea route between India and China and controlled much of the trade across the Malay Peninsula. Its people probably spoke an early form of Khmer, while its rulers adopted Sanskrit, Indian scripts and the worship of Shiva and Vishnu as well as the Buddha. A founding legend, told in both Chinese and later Khmer versions, relates that a Brahmin named Kaundinya married a local naga princess, Soma. Envoys from the Chinese kingdom of Wu, Kang Tai and Zhu Ying, visited Funan around 245.

In the sixth and seventh centuries Chinese sources name a new power, Chenla, based further inland. Earlier historians described Chenla conquering Funan, but scholars now read the inscriptions as showing more continuity, with Khmer kings shifting power from the coast to the rice plains. King Ishanavarman I built his capital at Sambor Prei Kuk in the early seventh century, whose brick temples are among the oldest in the country. In the eighth century Chenla split into rival principalities, and parts of the south came under the influence of Java and Srivijaya.

In 802 a ruler named Jayavarman II, who had spent time in Java, held a ceremony on the Kulen hills north of the Tonle Sap that proclaimed him chakravartin, universal monarch, and declared his independence from Java. This act is traditionally taken as the foundation of the Khmer Empire. His successors built a series of capitals in the Angkor region. Indravarman I and Yasovarman I, at the end of the ninth century, created the city of Yasodharapura and began the vast reservoirs, or barays, that stored water and defined the city's sacred geography; the West Baray, built in the eleventh century, is about eight kilometres long. Rulers presented themselves as protectors of the gods, chiefly Shiva and Vishnu, in the Hindu tradition, and built state temples in the form of Mount Meru. Jayavarman IV briefly moved the capital to Koh Ker in the tenth century, and Suryavarman I, who seized Angkor around 1006, expanded the empire into what is now Thailand.

The empire reached its widest extent under Suryavarman II, who reigned from 1113 to about 1150, when Khmer authority stretched over much of today's Thailand, Laos and southern Vietnam. He built Angkor Wat, dedicated to Vishnu, the largest religious monument in the world, whose reliefs show his court and armies. His wars against Dai Viet and the kingdom of Champa were less successful, and in 1177 a Cham army sailed up the Mekong and the Tonle Sap and sacked Angkor.

Jayavarman VII, a Mahayana Buddhist, drove out the Cham, was crowned in 1181 and became the greatest builder in Khmer history. He enclosed a new capital, Angkor Thom, with its central temple, the Bayon, whose towers bear huge serene faces, and built Ta Prohm, Preah Khan, Banteay Kdei, roads with rest houses and more than a hundred hospitals across the empire. Recent surveys using airborne laser scanning have shown that greater Angkor was a sprawling low-density city of houses, canals and rice fields covering around a thousand square kilometres, the most extensive pre-industrial urban complex known, home to perhaps 750,000 people at its height. Its society rested on rice farming, labour owed to temples and the state, and slaves taken in war or from hill peoples.

In 1296 and 1297 the Chinese envoy Zhou Daguan, sent by the Yuan dynasty, lived at Angkor and wrote the only detailed eyewitness description of its daily life, from markets and festivals to the king's processions. By then Theravada Buddhism, spread by monks from Sri Lanka, was winning over the population, and stone inscriptions and temple building gradually ceased after the early fourteenth century.

The causes of Angkor's decline are still debated. Historians point to the rise of the Thai kingdoms of Sukhothai and the Ayutthaya Kingdom, the shift of trade to the coast, the change of religion, and, according to recent research, the breakdown of Angkor's waterworks during decades of drought and flood in the fourteenth and fifteenth centuries. Ayutthaya attacked Angkor in 1431, and soon afterwards King Ponhea Yat moved the court south towards the confluence of the Mekong and the Tonle Sap, the site of Phnom Penh. Angkor Wat itself was never wholly abandoned and remained a Buddhist pilgrimage centre.

The new kingdom, with its capitals at Phnom Penh, Longvek and later Oudong, prospered from river and sea trade in the sixteenth century, attracting Chinese, Malay, Japanese and Portuguese merchants. But it was caught between two expanding neighbours. Ayutthaya captured Longvek in 1594, and Spanish and Portuguese adventurers from Manila meddled in the succession in the 1590s. In the seventeenth century Vietnamese settlers spread into the Mekong delta, and the Khmer town of Prey Nokor became Saigon, now Ho Chi Minh City, cutting Cambodia off from the sea routes of the delta. Rival princes sought Siamese or Vietnamese backing, and by the early nineteenth century Cambodia paid tribute to both. In the 1830s the Vietnamese emperor Minh Mang tried to absorb the country, provoking revolts, until a war between Siam and Vietnam ended in 1847 with King Ang Duong crowned under joint protection.

In August 1863 Ang Duong's son, King Norodom, signed a treaty placing Cambodia under the protection of France, which had recently taken southern Vietnam. French control tightened through the 1884 convention, which provoked a revolt across the country in 1885 and 1886, and in 1887 Cambodia became part of French Indochina. By the end of the century the king's authority barely extended beyond the palace. In 1907 France obtained the return of Battambang and Siem Reap, including Angkor, from Siam. French scholars cleared and restored the temples, and Angkor became a symbol of national identity. Colonial rule brought roads, rubber plantations and heavy taxes, but little education for Cambodians.

During World War II Vichy France lost Battambang and Siem Reap province to Thailand after a brief war in 1941, and the French placed the eighteen-year-old Norodom Sihanouk on the throne. Troops of the Empire of Japan were stationed in the country, and in March 1945 Japan overthrew the French administration and had Sihanouk declare independence. France returned in October 1945, and the lost provinces were restored in 1946. Sihanouk's campaign for independence, alongside armed resistance by the Khmer Issarak and communist forces allied with the Viet Minh, led France to transfer sovereignty, and Cambodia became independent on 9 November 1953.

In 1955 Sihanouk abdicated in favour of his father so that he could enter politics, and his movement, the Sangkum Reastr Niyum, won every seat in parliament in that year's election. Sihanouk dominated the country for fifteen years as prime minister and then head of state, combining royal prestige with authoritarian control and a policy of neutrality in the Cold War. As the Vietnam War escalated he broke with the United States in 1965 and quietly allowed North Vietnamese forces to use bases along the eastern border and supplies shipped through the port of Sihanoukville. At home a small communist movement, led by Paris-educated radicals including Saloth Sar, later known as Pol Pot, Ieng Sary and Son Sen, went underground and in 1968 launched an armed insurgency. Sihanouk called them the Khmer Rouge, the Red Khmers. In 1969 the United States began secret bombing of the border areas.

On 18 March 1970, while Sihanouk was abroad, the National Assembly deposed him, led by the prime minister General Lon Nol and Prince Sisowath Sirik Matak. The new government sided with the United States, which, with South Vietnam, sent ground troops into eastern Cambodia in April and May 1970. In October the monarchy was abolished and the Khmer Republic proclaimed. Sihanouk, in exile in Beijing, allied with his former enemies, the Khmer Rouge, whose movement grew with his prestige, with Chinese arms and, at first, with North Vietnamese help. American bombing intensified until August 1973, killing many civilians; historians debate how much it helped the Khmer Rouge recruit, but many see it as a significant factor. Corruption and military defeats undermined the republic, and more than two million refugees crowded into Phnom Penh and other cities.

The Khmer Rouge took Phnom Penh on 17 April 1975 and within days forced its entire population, perhaps two million people, into the countryside at gunpoint; other towns were emptied in the same way. The regime, which called the country Democratic Kampuchea, abolished money, markets, schools, private property and religion, and set out to build a purely agrarian communist society starting from what it called Year Zero. People were organised into collectives and forced to work long hours in the fields and on irrigation projects on starvation rations. City dwellers, known as new people, were treated as suspect. Former officials, soldiers, teachers and professionals were hunted down and executed, often with their families, and people could be killed for wearing glasses, speaking a foreign language or mourning the dead.

What happened is generally recognised as the Cambodian genocide. Between 1.5 and 2 million people died, from execution, starvation, overwork and untreated disease, around a quarter of a population of under eight million. The Khmer Rouge singled out ethnic Vietnamese, Chinese and Thai minorities and the Muslim Cham, whose communities were broken up and many of whose members were massacred, and Buddhist monks were defrocked or killed and most temples destroyed. Within the party, paranoid purges consumed thousands of cadres; at the security prison S-21 in a former Phnom Penh school, Tuol Sleng, between 14,000 and 20,000 people were tortured into confessions and then killed at Choeung Ek, the best known of the many killing fields. In 1978 the regime massacred tens of thousands of people in the Eastern Zone, accused by the leadership of being Khmers with Vietnamese minds.

Democratic Kampuchea was backed by China and hostile to Vietnam, and its troops repeatedly attacked Vietnamese border villages. On 25 December 1978 Vietnam invaded with a front of Cambodian defectors, including Heng Samrin and Hun Sen, and captured Phnom Penh on 7 January 1979.

Vietnam installed the People's Republic of Kampuchea, with Heng Samrin as head of state. The Khmer Rouge retreated to the jungles along the Thai border, and hundreds of thousands of Cambodians fled to camps in Thailand as famine struck in 1979 and 1980. Because the conflict was part of the rivalry between China and the Soviet Union, which supported Vietnam, China, the United States and most Western and South-east Asian governments refused to recognise the new government. A coalition of Sihanouk's royalists, a republican group and the Khmer Rouge kept Cambodia's seat at the United Nations, and the Khmer Rouge continued a guerrilla war. Hun Sen became prime minister in 1985.

As the Cold War ended, Vietnam withdrew its troops in 1989, and on 23 October 1991 the factions signed the Paris Peace Agreements. The United Nations Transitional Authority in Cambodia, with some 22,000 personnel, took temporary charge, repatriated about 370,000 refugees from Thailand and organised elections in May 1993, in which about 90 per cent of eligible voters took part despite a Khmer Rouge boycott. The royalist FUNCINPEC party of Prince Norodom Ranariddh won the most votes, but Hun Sen's Cambodian People's Party (CPP) forced a power-sharing arrangement with two prime ministers. A new constitution restored the monarchy in September 1993, with Sihanouk again king.

In July 1997 Hun Sen ousted Ranariddh in a violent coup, and the CPP has dominated the country ever since. The Khmer Rouge movement disintegrated through defections; Pol Pot died in April 1998 in its last stronghold at Anlong Veng, and by 1999 the insurgency was over. Cambodia joined ASEAN in 1999. Sihanouk abdicated in 2004 in favour of his son, Norodom Sihamoni. A tribunal established with the United Nations, the Extraordinary Chambers in the Courts of Cambodia, convicted the head of S-21, Kang Kek Iew, known as Duch, in 2010, and the senior leaders Nuon Chea and Khieu Samphan of crimes against humanity in 2014; in 2018 it found them guilty of genocide against the Vietnamese, and Nuon Chea also of genocide against the Cham.

Garment exports, tourism to Angkor, which became a World Heritage Site in 1992, and heavy Chinese investment have driven rapid economic growth, though corruption, land seizures and landmines left from the wars remain serious problems. Politics has grown more closed: after a strong opposition showing in 2013, the Supreme Court dissolved the main opposition party, the Cambodia National Rescue Party, in 2017, and the CPP won every seat in the 2018 election. After another election in July 2023 from which the main opposition party was excluded, Hun Sen handed the premiership to his son Hun Manet, who took office on 22 August 2023, while Hun Sen became president of the Senate in 2024.

A long-running border dispute with Thailand, centred on land around the temple of Preah Vihear and other frontier temples, escalated into armed clashes on 24 July 2025, with each side accusing the other of starting the fighting. More than 200,000 people were displaced before a ceasefire on 28 July. Fighting resumed in December 2025 and ended with a new ceasefire on 27 December, which was still holding, amid mutual mistrust, in mid-2026.