Cambodia becomes a French protectorate in 1863. Complete independence is granted in November 1953. Prince Norodom Sihanouk becomes head of state and head of government. His 16-year rule is soon destabilised by the war in Vietnam. Sihanouk establishes ties with North Vietnam, the Viet Cong (South Vietnamese communists) and China and distances the country from the United States, which he believes is plotting against him. In November 1963 Sihanouk terminates an aid program run by the US and in May 1965, as the war spills into Cambodia, breaks relations completely.
Meanwhile, domestic opposition to Sihanouk starts to mount. Disaffected groups begin to go underground and take up arms. Included among the groups is the Khmer Rouge, the radical wing of the Kampuchean Communist Party. The Khmer Rouge is led by Saloth Sar, later to be known to the world as Pol Pot. More background.
Born on 19 May 1925 in Prek Sbauv in Kampong Thum province, north of Phnom Penh. His father is a prosperous farmer and his family has connections to the Cambodian royal family.
1931 - At the age of six he moves to Phnom Penh to live with his brother, an official at the royal palace. He learns the rudiments of Buddhism during a brief stay at a pagoda near the royal palace before receiving his formal education at a number of French language schools and at a Catholic college.
1946 - While serving with the anti-French resistance under Vietnam's Ho Chi Minh, he joins the outlawed Indochinese Communist Party.
1949 - Pol Pot wins a government scholarship to study radio electronics in Paris. He fails to obtain a degree but becomes enthralled by writings on Marxism and revolutionary socialism and forges bonds with other like-minded young Cambodians studying in the metropolis, including Ieng Sary, Khieu Samphan, Song Sen and the sisters Khieu Ponnary and Khieu Thirith. The members of this so-called "Paris student group" are destined to become the leaders of the Khmer Rouge.
While in Paris, Pol Pot also joins the French Communist Party and helps transform the Association of Khmer Students into a leftist forum opposed to the Cambodian monarchy.
In a pamphlet titled 'Monarchy or Democracy' he writes, "(The monarchy) is a vile pustule living on the blood and sweat of the peasants. Only the National Assembly and democratic rights give the Cambodian people some breathing space. ... The democracy which will replace the monarchy is a matchless institution, pure as a diamond."
1951 - The Indochinese Communist Party, which is dominated by the Vietnamese, is reorganised in September into three separate units representing Vietnam, Cambodia and Laos, although the Vietnamese continue to supervise the smaller movements. The Cambodian unit is named the Kampuchean People's Revolutionary Party (KPRP).
1953 - After his scholarship is revoked, Pol Pot returns to Cambodia and throws himself into work for the KPRP, first in the Kampong Cham province northwest of Phnom Penh and then in the capital itself. He also travels to the east of the country to meet with the Vietnamese communists.
He supports himself by teaching history and geography at a private school, where he is well liked and respected by his pupils.
1956 - Pol Pot marries Khieu Ponnary.
1960 - In late September Pol Pot and the Paris student group take control of the KPRP, renaming it the Workers' Party of Kampuchea (WPK) and turning it away from its Vietnamese patrons. Pol Pot is elected to the number three position on the party's Central Committee, allowing him to build a strong faction.
1963 - In February Pol Pot is chosen as the WPK's general secretary, the highest position in the party, following the mysterious disappearance of the previous incumbent. In July he and most of the WPK Central Committee leave Phnom Penh to organise an insurgency base, Office 100, on the border with Vietnam in the country's northeast.
1965 - Pol Pot walks the recently completed Ho Chi Minh Trail to Hanoi, the capital of North Vietnam, for consultations with the North Vietnamese communists, who are critical of his nationalist agenda and tell him to delay an armed struggle in Cambodia until the US is driven from Vietnam.
1966 - He receives a better reception when he makes his first visit to China, where the Cultural Revolution has just been launched. He is influenced by the leading radicals supporting the movement and by Mao Tse-Tung's concept of a continuous revolution. He returns to Cambodia determined to further loosen ties with the Vietnamese communists.
The WPK changes its name again, to the Kampuchean Communist Party, though the Cambodian communists are now more commonly known as the Khmer Rouge. The party's all-powerful Central Committee, headed by Pol Pot, is referred to as Angkar (organisation).
1967 - Returning from a trip to North Vietnam, Pol Pot takes refuge in the northeast of Cambodia. He lives with a hill tribe and is impressed by their simple, non-material way of life, seeing it as a realisation of communist ideals.
Insurrection breaks out in the west of Cambodia at the start of the year. It is suppressed brutally but not completely and spreads. By the end of 1968 unrest is reported in 11 of the country's 18 provinces. By the end of the decade, the Khmer Rouge completely control almost all the mountainous regions on the border with Vietnam.
1968 - The Khmer Rouge establish the Revolutionary Army of Kampuchea in January. Aided by the United States, the army launches a small and ineffectual insurgency campaign.
1969 - In March the US begins secret bombing raids on Vietnamese communist bases and supply routes inside Cambodia (dubbed the Menu Series). Authorised by the newly installed US President, Richard M. Nixon, and directed by his national security adviser, Henry Kissinger, the raids are launched without the knowledge of the US Congress.
US bombing raids into Cambodia continue until 1973. All told 539,129 tons of ordnance are dropped on the country, much of it in indiscriminate B-52 carpet-bombing raids. The tonnage is about three and a half times more than that (153,000 tons) dropped on Japan during the Second World War.
Thousands of Cambodians die but the raids are militarily ineffective. The Central Intelligence Agency (CIA) reports that the bombing raids are serving to increase the popularity of the Khmer Rouge among the affected Cambodian population.
1970 - Prince Sihanouk travels abroad in January to solicit Chinese and Soviet assistance to roll-back the Vietnamese communist incursions into Cambodia.
On 18 March, Sihanouk's right-wing opponents within the government seize the opportunity, banning his return from China and installing Defence Minister Lon Nol as premier of the newly proclaimed Khmer Republic. The coup is supported by the CIA.
The new, US-backed government stirs anti-Vietnamese sentiment and initiates ineffectual military operations against the Vietnamese communist troops in Cambodia. Simultaneously, the Lon Nol government cancels an agreement allowing North Vietnam to use the port at Sihanoukville.
In April US President Nixon authorises the invasion of Cambodia by a joint US-South Vietnamese force of 30,000 troops. The joint force is tasked with destroying Vietnamese communist bases inside Cambodia, but only succeeds in pushing the Vietnamese further into the country.
In China, Sihanouk forms a government in exile and builds an alliance with the Khmer Rouge. Both Sihanouk and the Khmer Rouge are intent on achieving the overthrow of the Lon Nol government.
The Khmer Rouge receive military aid and training from the North Vietnamese and support from China and are quickly transformed into an effective fighting force, expanding from a small guerrilla outfit of less than 5,000 to an army of 100,000 in a matter of months.
By June, the Lon Nol government troops have been swept from the entire northeastern third of the country. Areas in the south and southwestern parts of the country are also overrun. By 1973, the Khmer Rouge control nearly 60% of Cambodia's territory and 25% of its population.
1973 - In an attempt to prop-up the Lon Nol government, halt the Khmer Rouge advance and destroy Vietnamese communist bases in Cambodia, the Nixon administration secretly intensifies the bombing of the country, without government authorisation, and despite having signed a peace agreement with the North Vietnamese on 27 January.
1974 - The Khmer Rouge capture the old capital of Odongk, north of Phnom Penh, in March. In a foretaste of what is to come, the city is destroyed, its 20,000 inhabitants are dispersed into the countryside, and teachers and public servants are executed.
1975 - Now in control of most of the Cambodian countryside, the Khmer Rouge surround and isolate the capital Phnom Penh, which has swollen with refugees fleeing the Khmer Rouge and the US bombers. The noose steadily tightens. On 17 April, Phnom Penh falls. Within days the city's entire population of over two million is marched into the countryside at gunpoint.
Pol Pot declares Year Zero and directs a ruthless program to "purify" Cambodian society of capitalism, Western culture, religion and all foreign influences. A new, isolated and totally self-sufficient Maoist agrarian state is to be created. No opposition will be tolerated.
Foreigners are expelled, embassies closed, and the currency abolished. Markets, schools, newspapers, religious practices and private property are outlawed.
Members of the Lon Nol government, public servants, police, military officers, teachers, ethnic Vietnamese, Christian clergy, Muslim leaders, members of the Cham Muslim minority, members of the middle-class, and the educated are identified and executed.
Towns and cities are emptied and their former inhabitants are deemed "April 17th people" or "new people". The country's entire population is forced to relocate to agricultural collectives, the so-called "killing fields". Workers exist in primitive conditions. Families are separated. Buddhist monks are defrocked and forced into labour brigades. Former city residents are subjected to unending political indoctrination. Children are encouraged to spy on adults.
An estimated 1.5 million are worked or starved to death, die of disease or exposure, or are summarily executed for infringements of camp discipline. Infringements punishable by death include not working hard enough, complaining about living conditions, collecting or stealing food for personal consumption, wearing jewellery, engaging in sexual relations, grieving over the loss of relatives or friends and expressing religious sentiments.
Khmer Rouge records from the Tuol Sleng interrogation and detention centre in Phnom Penh (also known as S-21) show that 14,499 "antiparty elements", including men, women and children, are tortured and executed from 1975 to the first six months of 1978. Only seven of those detained at the centre leave it alive.
At least 20 other similar centres operate throughout the country.
Terror and paranoia reign, reaching a climax in 1977 and 1978 when Pol Pot launches a bloody purge against the "hidden enemies, burrowing from within" and the Khmer Rouge cadres turn on themselves. At least 200,000 are executed.
1976 - The Khmer Rouge declare the new state of Democratic Kampuchea on 5 January. Prince Sihanouk is appointed as head of state. He resigns as after witnessing the deprivations of the agricultural collectives and is placed under virtual house arrest in Phnom Penh. Pol Pot is made prime minister, although his identity and the identities of other members of the Angkar leadership group are kept secret from non-members. To most inside and outside of Cambodia, Pol Pot is a shadowy figure known as Brother Number One. The subordinate leaders of the party are known as Brother Number Two, Brother Number Three, and so on.
It is not revealed that Angkar is in fact the Kampuchean Communist Party until September 1977.
1977 - Although almost the entire population is involved in agricultural production, Cambodia experiences food shortages, resulting in many more deaths. Conflicts along the Thai, Laotian and Vietnamese borders escalate. Relations with Vietnam are broken in December. At the same time, Vietnam begins to turn away from China towards the Soviet Union.
Pol Pot, meanwhile, makes a state visit to China, which promises ongoing support, including military assistance for any conflict between Cambodia and Vietnam.
1978 - Vietnam deploys division-sized units along the Cambodian border and sponsors the establishment of an anti-Pol Pot movement called the Kampuchean (or Khmer) National United Front for National Salvation.
The Vietnamese launch a full-scale military invasion of Cambodia on 25 December. The Khmer Rouge are rapidly pushed aside. Phnom Penh is captured on 7 January 1979. Prince Sihanouk flees to China on the last flight out of the capital. Pol Pot and the defeated Khmer Rouge retreat to the country's remote western regions from where they wage a fitful guerrilla war destined to last a further 20 years.
Between one and three million Cambodians, or about one quarter of the country's entire population of about seven million, have died during the three years, eight months and 20 days of Pol Pot's rule. On a per capita basis the Khmer Rouge "revolution" is easily the deadliest in modern Asian history.
1979 - Three days after the fall of Phnom Penh, the Vietnamese occupying forces establish the People's Republic of Kampuchea (PRK), governed by the Kampuchean People's Revolutionary Party (KPRP) and headed by Heng Samrin, a former Khmer Rouge military commander. Between 125,000 and 70,000 Vietnamese troops remain in Cambodia until 1989.
Already at war with the Khmer Rouge, the PRK faces further resistance from two new insurgent movements - the noncommunist Khmer People's National Liberation Front (KPNLF) headed by Son Sen, and the National United Front for an Independent, Neutral, Peaceful, and Cooperative Cambodia (FUNCINPEC) headed by Prince Sihanouk.
In December, Pol Pot is replaced as prime minister of the Khmer Rouge "government" by Khieu Samphan. Pol Pot remains as leader of the Kampuchean Communist Party and the Khmer Rouge armed forces.
1980 - The United Nations (UN) continues to recognise Pol Pot's Democratic Kampuchea as the legal representative of Cambodia. The position is backed by China, the US and ASEAN (the Association of Southeast Asian Nations), all of which are concerned by the improving relations between Vietnam and the Soviet Union and the spread of Soviet-backed communism in the region.
It is reported that the Khmer Rouge are receiving military backing from China and the US. It is also reported that a former deputy director of the CIA visits Pol Pot's operational base in November. While the UN withholds development aid from the KPRP government, the World Food Program supplies the Khmer Rouge with food worth US$12 million during 1980.
Meanwhile, Pol Pot's wife, Khieu Ponnary, goes insane. He divorces her and in 1985 marries a much younger second wife with who he has a daughter. Khieu Ponnary dies in 2003.
1982 - On 22 June the Khmer Rouge, KPNLF and FUNCINPEC join in a coalition (the Coalition Government of Democratic Kampuchea) against the Vietnamese. The agreement has been brokered by ASEAN. Prince Sihanouk is chosen as the coalition's president, Khieu Samphan is vice president and Son Sen is prime minister.
The coalition, which proposes a general election under UN supervision once the Vietnamese have withdrawn, is recognised by the UN as the lawful government of Cambodia. The Khmer Rouge no longer have any legal claim on the country.
1985 - Pol Pot officially resigns as commander of the Khmer Rouge military forces, although he retains a supervisory role.
1989 - The withdrawal of Vietnamese troops from Cambodia is completed in September. The PRK remains in power, headed by Hun Sen, a former member of the Khmer Rouge and later ally of the Vietnamese. The country is renamed Cambodia and the constitution amended. Renewed fighting between the PRK troops and the opposition forces, including the Khmer Rouge, breaks out on the country's western frontier with Thailand.
1991 - On 23 October the four factions (PRK, KPNLF, FUNCINPEC, Khmer Rouge) finally sign a peace treaty establishing a temporary coalition government under the supervision of a UN peacekeeping force. Prince Sihanouk returns to Cambodia and is named president.
1993 - Cambodia's first multiparty elections since 1972 are held in May, although they are boycotted by the Khmer Rouge, which claims that the Vietnamese are still covertly occupying the country. When no single party wins a majority, the KPNLF and FUNCINPEC form a coalition with two smaller groups.
However, Hun Sen refuses to give up control of the government, leading to a power-sharing arrangement between the coalition and the PRK.
Pol Pot goes into hiding and continues the insurgency against the government. He is reported to be in command of a shrinking and demoralised Khmer Rouge guerrilla force based in the Phnum Dangrek Range near the northern border with Thailand. Funding for the movement is obtained through the sale of gem mining and logging concessions to Thai interests, with the revenue estimated to be worth about US$200 million a year.
1996 - The Khmer Rouge begin to split. In August, Ieng Sary, Khmer Rouge foreign minister and Brother Number Three, defects to the Cambodian armed forces, bringing about 4,000 guerrillas with him. Ieng Sary subsequently names Pol Pot as the "sole and supreme architect" of the Khmer Rouge's "line, strategy and tactics". It is the beginning of the end for the Khmer Rouge, who are now reduced to just a few thousand cadres.
1997 - In June, Pol Pot becomes convinced that Son Sen, the Khmer Rouge minister for defence and his friend for 40 years, is collaborating with the Cambodian Government and orders his execution. Sen's wife and children are also killed.
Pol Pot is subsequently arrested by Ta Mok, the Khmer Rouge military commander and Brother Number Five. On 25 July a "peoples' tribunal" sentences Pol Pot to life imprisonment for Sen's murder. Pol Pot is reported to be ailing and near death.
During the trial, Pol Pot agrees to an interview with Nate Thayer, a journalist with the 'Far Eastern Economic Review'.
"First, I want to let you know that I came to join the revolution, not to kill the Cambodian people," Pol Pot tells Thayer.
"Look at me now. Do you think ... am I a violent person? No. So, as far as my conscience and my mission were concerned, there was no problem. This needs to be clarified. ...
"My experience was the same as that of my movement. We were new and inexperienced and events kept occurring one after the other which we had to deal with. In doing that, we made mistakes as I told you. I admit it now and I admitted it in the notes I have written.
"Whoever wishes to blame or attack me is entitled to do so. I regret I didn't have enough experience to totally control the movement. On the other hand, with our constant struggle, this had to be done together with others in the communist world to stop Kampuchea becoming Vietnamese.
"For the love of the nation and the people it was the right thing to do but in the course of our actions we made mistakes."
Meanwhile, Hun Sen and the PRK seize full control of the Cambodian Government in July, using force of arms to oust the coalition in an action that amounts to a military coup.
1998 - Pol Pot dies in the evening of 15 April, reportedly from heart failure, although the cause of his death remains unclear. Hours earlier he had learned from a radio broadcast that Ta Mok was willing to hand him over to the government for trial. His body is cremated on a pyre of old car tyres beside a village latrine. The site is later enclosed by a crude timber shelter roofed with old sheets of corrugated iron.
In May, Cambodian armed forces capture the last stronghold of the Khmer Rouge in the country.
1999 - In February the last remaining members of the Khmer Rouge are incorporated into the Cambodian armed forces. In March, Ta Mok, the last Khmer Rouge leader at large, is arrested. He dies in custody on 21 July 2006.
Other senior leaders of the Khmer Rouge are eventually brought to justice before a specially convened tribunal known as the Extraordinary Chambers in the Courts of Cambodia. The trials begin in 2009.
Kaing Khek Iev, the governor of the Tuol Sleng detention centre, is charged with crimes against humanity and war crimes. He is found guilty as charged and sentenced to 35 years jail. Following an appeal, the sentence is increased to life.
Noun Chea is charged with genocide, crimes against humanity and war crimes, including "murder, torture, imprisonment, persecution, extermination, deportation, forcible transfer, enslavement and other inhumane acts". He is found guilty of crimes against humanity and sentenced to life in prison. Nuon Chea was one of the members of the Paris student group. He was Brother Number Two in the Khmer Rouge hierarchy, and a hard-line and unrepentant supporter of Pol Pot.
Ieng Sary and his wife, Khieu Thirith, are charged with genocide and crimes against humanity. Ieng Sary is also charged with war crimes. Ieng Sary dies on 14 March 2013. Ieng Sary was Khmer Rouge foreign minister and Brother Number Three. Khieu Thirith is declared medically unfit to face trial due to dementia. She is set free on 16 September 2012 and dies on 22 August 2015.
Khieu Samphan is charged with genocide, crimes against humanity and war crimes. He is found guilty of crimes against humanity and sentenced to life in prison. Khieu Samphan was head of state of the Khmer Rouge government.
Prince Norodom Sihanouk has summed up the character of one of the worst genocidal dictators of the 20th Century, saying, "Pol Pot is very charming. ... His face, his behaviour is very polite, but he is very, very cruel."
Others who knew him have elaborated on this description, calling Pol Pot calm, cold-blooded, extremely secretive, and above all paranoid - traits that allowed him to oversee the genocide of hundreds of thousands of innocent men, women and children.
The last word here goes again to Sihanouk.
"Pol Pot does not believe in God but he thinks that heaven, destiny, wants him to guide Cambodia in the way he thinks it the best for Cambodia, that is to say, the worst. Pol Pot is mad, you know, like Hitler."