History:Spanish dollar: 17th-19th centuries

Spanish dollar: 17th-19th centuries

In the 17th and 18th century, the use of silver Spanish dollars or "pieces of eight" spread from the Spanish territories in the Americas westwards to Asia and eastwards to Europe forming the first ever worldwide currency. Spain's political supremacy on the world stage, the importance of Spanish commercial routes across the Atlantic and the Pacific, and the coin's quality and purity of silver helped it become internationally accepted for over two centuries. It was legal tender in Spain's Pacific territories of the Philippines, Micronesia, Guam and the Caroline Islands and later in China and other Southeast Asian countries until the mid 19th century. In the Americas it was legal tender in all of South and Central America (except Brazil) as well as in the U.S. and Canada until the mid-19th century. In Europe the Spanish dollar was legal tender in the Iberian Peninsula, in most of Italy including: Milan, the Kingdom of Naples, Sicily and Sardinia, as well as in the Franche-Comt (France), and in the Spanish Netherlands. It was also used in other European states including the Austrian Habsburg territories.

19th - 20th centuries

Prior to and during most of the 1800s, 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.

In the period following the Bretton Woods Conference of 1944, exchange rates around the world were pegged against the United States dollar, which could be exchanged for a fixed amount of gold. This reinforced the dominance of the US dollar as a global currency.

Since the collapse of the fixed exchange rate regime and the gold standard and the institution of floating exchange rates following the Smithsonian Agreement in 1971, most currencies around the world have no longer been pegged against the United States dollar. However, as the United States remained the world's preeminent economic superpower, most international transactions continued to be conducted with the United States dollar, and it has remained the de facto world currency.

Only two serious challengers to the status of the United States dollar as a world currency have arisen. During the 1980s, the Japanese yen became increasingly used as an international currency[citation needed], but that usage diminished with the Japanese recession in the 1990s. More recently, the euro has increasingly competed with the United States dollar in international finance.