Postage stamps and postal history of Costa Rica change in currency from "Reales" to the new Pesos and "Centavos", the issue of 1863 was surcharged with new values for postal use: 1 Centavos, 2 Centavos, 5 Centavos (all over the Medio Real stamp), 10 Centavos (over Dos Reales) and 20 Centavos (over Cuatro Reales). The 5, 10 and 20 Centavos were also surcharged "U.P.U." Costa Rican stamps were issued overprinted "Guanacaste" in 1885-89 following war with Nicaragua over the sovereignty of Guanacaste. The first issue in the new "Colón" currency was dated 1900 and put into circulation in 1901. It consists of ten stamps with values ranging from
World currency Habsburg territories. Prior to and during most of the 19th century, international trade was denominated in terms of currencies that represented weights of gold. Most national currencies at the time were in essence merely different ways of measuring gold weights (much as the yard and the meter both measure length and are related by a constant conversion factor). Hence some assert that gold was the world's first global currency. The emerging collapse of the international gold standard around the time of World War I had significant implications for global trade. Before 1944, the world reference currency was the United Kingdom's