Information about currency: Spanish Dollar

The "real de a ocho", also known as the Spanish dollar, the eight-real coin, or the piece of eight (Spanish peso de ocho), is a silver coin of approximately 38 mm diameter, worth eight reales, that was minted in the Spanish Empire after 1598. Its purpose was to correspond to the German thaler.

The Spanish dollar was widely used by many countries as international currency because of its uniformity in standard and milling characteristics. Some countries countersigned the Spanish dollar so it could be used as their local currency.

The Spanish dollar was the coin upon which the original United States dollar was based, and it remained legal tender in the United States until the Coinage Act of 1857. Because it was widely used in Europe, the Americas, and the Far East, it became the first world currency by the late 18th century. Aside from the U.S. dollar, several other existing currencies, such as the Canadian dollar, the Japanese yen, the Chinese yuan, the Philippine peso, and several currencies in Latin America, were initially based on the Spanish dollar and other 8-real coins. Diverse theories link the origin of the "$" symbol to the columns and stripes that appear on one side of the Spanish dollar.

The term peso was used in Spanish to refer to this denomination, and it became the basis for many of the currencies in the former Spanish colonies, including the Argentine, Bolivian, Chilean, Colombian, Costa Rican, Cuban, Dominican, Ecuadorian, Guatemalan, Honduran, Mexican, Nicaraguan, Paraguayan, Philippine, Puerto Rican, Peruvian, Salvadoran, Uruguayan, and Venezuelan pesos.

Millions of Spanish dollars were minted over the course of several centuries. They were among the most widely circulating coins of the colonial period in the Americas, and were still in use in North America and in South-East Asia in the 19th century.

The coin was minted with several different designs at various mints in Spain and the New World, having gained wide acceptance beyond Spain's borders. Thanks to the vast silver deposits that were found in Mexico (for example, at Taxco and Zacatecas) and Potosí in modern-day Bolivia, and to silver from Spain's possessions throughout the Americas, mints in Mexico and Peru also began to strike the coin. The main New World mints for Spanish dollars were at Potosí, Lima, and Mexico City (with minor mints at Bogotá, Popayán, Guatemala City, and Santiago), and silver dollars from these mints could be distinguished from those minted in Spain by the Pillars of Hercules design on the reverse. In the 19th century, the coin's denomination was changed to 20 reales (based on 20 reales de vellón) and finally 2 escudos.

Spain's adoption of the peseta in 1869 and its joining the Latin Monetary Union meant the effective end of the last vestiges of the Spanish dollar in Spain itself. However, the 5-peseta coin (or duro) was slightly smaller and lighter but was also of high purity (90%) silver.

In the 1990s, commemorative 2000-peseta coins were minted, similar in size and weight to the 8 reales and also with high fineness.