Until the 1970s, which a coup ended, a monarchy had ruled Cambodia since ancient times. In 1975 when the Khmer Rouge took over Cambodia, the country was renamed Democratic Kampochea (DK). The Khmer Rouge is also responsible for starting a war with Vietnam in 1977.
The Khmer Rouge was overthrown in 1979 by a group of Cambodian Communist Rebels, backed by 100,000 Vietnamese troops, who again changed the country's name. This time when they renamed it to the People's Republic of Kampochea (PRK), not many foreign governments recognized the government, thus allowing the DK to keep its place in the United Nations.
During the 1980s Vietnam had troops stationed in Cambodia and during this period the only legal political party was the Kampochean People's Revolutionary Party (KPRP) and ran the PRK under socialist guidelines. When Vietnam withdrew in 1989, Cambodia's name changed to the State of Cambodia (SOC) and they changed from socialism to free-market.
With the help of the United Nations, internal conflict within Cambodia was resolved with a peace accord which was signed in Paris in 1991. A UN protectorate was to help rule Cambodia until national elections were held in 1993.
When the elections were held, 20 political parties participated with two parties winning the majority of seats, FUNCINPEC and CPP (Cambodian People's Party, formerly known as KPRP).
Two prime ministers headed the government; Prince Norodom Ranariddh of FUNCINPEC was the first prime minister with Hun Sen of the CPP being the second prime minister. In September of 1993, a constitution was written up that restored the monarchy and established the Kingdom of Cambodia.
People's Republic of Kampuchea began printing their stamps in 1980. Printing of Mary stamps began in 1984.