Postage stamps and postal history of Mexico The regency had previously changed the official currency under which one peso equaled 8 reales to a decimal system in which one peso equaled 100 centavos. In making the conversion postal rates were rounded up, for example, the rate of one real being equal to 12.5 centavos was rounded up to 13 centavos. The stamps, as a result, were issued in values of 7c, 13c, 25c, and 50c. These stamps were issued with the year and invoice number and with or without the district name, but some issued in exchange for Eagle stamps were issued only with the Mexico City
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