currency of Cambodia as well as Siam and Laos. However, as a result of French intervention in the region, the tical in Cambodia was replaced in 1875 by the Cambodian franc. Cambodian Franc The franc was the currency of Cambodia between 1875 and 1885. It was equal to the French franc and was similarly subdivided into 100 centimes. It replaced the tical and was replaced by the piastre. French Indochinese piastre The piastre was introduced in French Indochina in 1885 at par with the Spanish-American silver dollar, and was in use until 1952. First riel (1953–1975) In 1953, the Cambodia branch of the Institut d'Émission des États du Cambodge, du Laos et du Vietnam issued notes dual denominated in piastre and riel with the riel being at par with the piastre. At the same time, the two other branches of the Institut had similar arrangements with the đồng in South Vietnam and the kip in Laos. The piastre itself was derived from Spanish pieces of eight (pesos). The riel was at first subdivided into 100 centimes (abbreviated to cent. on the coins) but this changed in 1959 to 100 sen (). For the first few years, the riel and piastre circulated alongside each other. The first riel banknotes were also denominated in piastres. First issue, 1955–56: 1 riel, 5 riels, 10 riels, 50 riels. Second issue, 1956: 1 riel, 20 riels, 50 riels, 100 riels, 500 riels. Third issue, 1956: 100 riels, 500 riels. Fourth issue, 1963: 5 riels, 10 riels, 100 riels. Fifth issue, 1972: 100 riels*, 500 riels, 1,000 riels*, 5,000 riels*. (* Unissued.) Coins: The 10, 20 and 50 centimes of 1953 and sen coins were minted in aluminum and were the same size as the corresponding att and xu (su) coins of Laos and South Vietnam (though without the holes in the Lao coins). A 1 riel coin about the size of a U.S. nickel was to be issued in 1970, as part of the United Nations' Food and Agriculture Organization's coin program, but was not released, perhaps due to the overthrow of the government of Norodom Sihanouk by Lon Nol. Khmer Rouge (1975–1980, 1993–1999) Although the Khmer Rouge printed banknotes, these notes were not issued as money was abolished after the Khmer Rouge took control of the country. Sixth issue, 1975: 0.1 riel (1 kak), 0.5 riels (5 kaks), 1 riel, 5 riels, 10 riels,