In the 1970s he was with the Khmer Rouge, his enemy the U.S.-backed Lon Nol regime.

CNN: BIG BURDEN

In March 1970, while Sihanouk was visiting the Soviet Union, General Lon Nol, then Cambodian Prime Minister, seized control of the government with American help.

BBC: Obituary: Norodom Sihanouk, former king of Cambodia

When a US-backed coup installed Lon Nol as Cambodia's leader, Sihanouk - by then alienated by US bombing raids on Vietnamese communist guerrillas inside Cambodia - was forced into exile in Beijing.

BBC: Cambodia former king Norodom Sihanouk dies aged 89