Cambodia is a country in South East Asia. At one time it was the centre of the ancient kingdom of the Khmer, and its capital was Angkor. The capital today is Phnom Penh. In 1953 Cambodia gained independence after nearly 100 years of French rule. In the 1960s the population of Cambodia was more than seven million mainly Buddhists who were ruled by Prince Sihanouk. In 1970 Prince Sihanouk was taken out of power in a military revolution. The leader of the new government who took power was lieutenant-general Lon Nol. When he took power, he also became the president of the 'Khmer Republic'. Prince Sihanouk who had been taken out of power, gathered his followers and joined with a communist guerrilla organisation known as the Khmer Rouge. They attacked Lon Nol's army and from here the civil war started.
Under Prince Sihanouk, Cambodia had also helped during the Vietnamese civil war by helping both sides a little.
When US-backed Lon Nol took over, US troops felt free to move into Cambodia to continue the bombing of the Viet Cong situated there. Essentially Cambodia had become a large part of the Vietnam battlefield. In the course of the next few years, American B-52 bombers killed up to 750,000 Cambodians in whilst trying to destroy the North Vietnamese supply lines - clearly devastating to Cambodia.
The Khmer Rouge leader was Pol Pot. He had been brought up in France and he was an great admirer of Maoist communism, and thus he was suspicious of Vietnam's relations with Cambodia. The heavy American bombardment of Cambodia, and Lon Nol's collaboration with America - which made him very unpopular, lost him supporters and drove new recruits to the Khmer Rouge. As well as this, the new followers were attracted...