A former French protectorate, Cambodia gained independence in 1953 as a constitutional monarchy with Norodom Sihanouk as king.
* 1955 Sihanouk abdicates to pursue political career.
* 1970 Right-wing coup led by Prime Minister Lon Nol deposes Sihanouk. Exiled Sihanouk forms Royal Government of National Union of Cambodia (GRUNC), backed by formerly hostile communist Khmer Rouge. Lon Nol proclaims Khmer Republic.
* 1974 GRUNC forces capture Phnom Penh. Prince Sihanouk head of state, Khmer Rouge assumes power. Hundreds of thousands die during radical social program.
* 1976 Country renamed Democratic Kampuchea. Elections. Sihanouk resigns; GRUNC dissolved. Khieu Samphan head of state; Pol Pot prime minister.
* 1977 Regime called the Communist Party of Kampuchea (CPK), led by Pol Pot.
* 1978 Vietnam invades, supported by Cambodian communists opposed to Pol Pot.
* 1979 Vietnamese capture Phnom Penh. CPK ousted by Kampuchean People's Revolutionary Party (KPRP), led by Pen Sovan. Khmer Rouge starts guerrilla war. Pol Pot held responsible for three million deaths and sentenced to death in absence. Vietnamese and DK (mostly Khmer Rouge) forces begin conflict on Thai border.
* 1980 Heng Samrin KPRP leader.
* 1982 Government-in-exile formed, including Khmer Rouge and Khmer People's National Liberation Front, headed by Prince Sihanouk; recognized by UN.
* 1988 Vietnam announces troop withdrawals. Khmer Rouge offensive. Khmer Rouge refuses to take part in peace talks.
* 1989 Vietnamese troops withdraw. Khmer Rouge forces make gains.
* 1990 UN Security Council approves plan for UN-monitored ceasefire and elections. Cambodian factions form Supreme National Council (SNC) but no agreement reached.
* 1991 SNC agree on elections. Factions sign accord. Sihanouk head of State of Cambodia. Khmer Rouge officials flee after attacks.
* 1992 Clashes between Cambodian troops and Khmer Rouge. UN ceasefire repeatedly violated.
* 1993 UN-supervised elections go ahead. UN peace operation leaves.
