[1][2] Detailed records of a political structure on the territory of what is now Cambodia first appear in Chinese annals in reference to Funan, a polity that encompassed the southernmost part of the Indochinese peninsula during the 1st to 6th centuries.
[4] By the 6th century a civilization, called Chenla or Zhenla in Chinese annals, firmly replaced Funan, as it controlled larger, more undulating areas of Indochina and maintained more than a singular centre of power.
Great achievements in administration, agriculture, architecture, hydrology, logistics, urban planning and the arts are testimony to a creative and progressive civilisation - in its complexity a cornerstone of Southeast Asian cultural legacy.
[3][38][39][40] Chinese annals[41] 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".
Exports ranged from forest products to precious metals and commodities such as gold, elephants, ivory, rhinoceros horn, kingfisher feathers, wild spices like cardamom, lacquer, hides and aromatic wood.
Under Fan Shih-man Funan maintained a formidable fleet and was administered by an advanced bureaucracy, based on a "tribute-based economy, that produced a surplus which was used to support foreign traders along its coasts and ostensibly to launch expansionist missions to the west and south".
Land Chenla acquired independence under Jayavarman II in 802 CE[74] Ancient Chinese records mention two kings, Shrutavarman and Shreshthavarman who ruled at the capital Shreshthapura located in modern-day southern Laos.
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.
The Mahidharapura dynasty – its first king was Jayavarman VI (1080 to 1107), which originated west of the Dângrêk Mountains in the Mun river valley discontinued the old "ritual policy", genealogical traditions and crucially, Hinduism as exclusive state religion.
The combination of sophisticated wet-rice agriculture, based on an engineered irrigation system and the Tonlé Sap's spectacular abundance in fish and aquatic fauna, as protein source guaranteed a regular food surplus.
A growing number of researchers relates the progressive over-exploitation of the delicate local eco-system and its resources alongside large scale deforestation and resulting erosion to the empires' eventual decline.
[82] Under king Suryavarman II (1113–1150) 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, its five towers representing Mount Meru is considered to be the most accomplished expression of classical Khmer architecture.
[88][89] However, most modern historians contest that several distinct and gradual changes of religious, dynastic, administrative and military nature, environmental problems and ecological imbalance[90] coincided with shifts of power in Indochina and must all be taken into account to make an interpretation.
[98][99] Wang Shi-zhen (王世貞), a Chinese scholar of the 16th century, remarked: "The official historians are unrestrained and are skilful at concealing the truth; but the memorials and statutes they record and the documents they copy cannot be discarded.
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.
[40] The original treaty left Cambodian sovereignty intact, but French control gradually increased, with important landmarks in 1877, 1884, and 1897, until by the end of the century the king's authority no longer existed outside the palace.
By the mid-1960s, parts of Cambodia's eastern provinces were serving as bases for North Vietnamese Army and National Liberation Front (NVA/NLF) forces operating against South Vietnam, and the port of Sihanoukville was being used to supply them.
Opposition to the government grew within the middle class and leftists including Paris-educated leaders like Son Sen, Ieng Sary, and Saloth Sar (later known as Pol Pot), who led an insurgency under the clandestine Communist Party of Kampuchea (CPK).
While visiting Beijing in 1970 Sihanouk was ousted by a military coup led by Prime Minister General Lon Nol and Prince Sisowath Sirik Matak in the early hours of 18 March 1970.
Simultaneous attacks around the perimeter of Phnom Penh pinned down Republican forces, while other CPK units overran fire bases controlling the vital lower Mekong resupply route.
Some historians, including Michael Ignatieff, Adam Jones[126] and Greg Grandin,[127] have cited the United States intervention and bombing campaign (spanning 1965–1973) as a significant factor which lead to increased support for the Khmer Rouge among the Cambodian peasantry.
"[129] Pol Pot biographer David P. Chandler writes that the bombing "had the effect the Americans wanted – it broke the Communist encirclement of Phnom Penh", but it also accelerated the collapse of rural society and increased social polarization.
[138] Owing to Chinese, U.S., and Western support, the Khmer Rouge-dominated Coalition Government of Democratic Kampuchea (CGDK) held Cambodia's UN seat until 1993, long after the Cold War had ended.
In late December 1978, Vietnamese forces launched a full invasion of Cambodia, capturing Phnom Penh on 7 January 1979 and driving the remnants of Democratic Kampuchea's army westward toward Thailand.
In many areas of the country people were rounded up and executed for speaking a foreign language, wearing glasses, scavenging for food, absent for government assigned work, and even crying for dead loved ones.
[150] 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.
[155] On 23 October 1991, the Paris Conference reconvened to sign a comprehensive settlement giving the UN full authority to supervise a cease-fire, repatriate the displaced Khmer along the border with Thailand, disarm and demobilise the factional armies, and prepare the country for free and fair elections.
Pre-election violence and intimidation was widespread, caused by SOC (State of Cambodia – made up largely of former PDK cadre) security forces, mostly against the FUNCINPEC and BLDP parties according to UNTAC.