Silver dollar of the Catholic Monarchs, after 1497 Reverse FERNANDVS ET ELISABET DEI GR[ATIA] "Ferdinand and Elisabeth, by the Grace of God" Displays the arms of the Catholic Monarchs post 1492, with Granada in base. Letter S on the left is the sign of the mint of Seville and VIII on the right i.e. eight in roman numerals. Obverse REX ET REGINA CASTELE LEGIONIS A[RAGONIS] "King and Queen of Castile, Leon, Aragon..." Displays the personal emblems of the monarchs: Ferdinand's arrows and Isabella's yoke.

Silver dollar of Philip V of Spain, 1739 Reverse VTRAQVE VNUM M[EXICO] 1739 "Both (are) one, Mexico [City Mint], 1739" Displays two hemispheres of a world map, crowned between the Pillars of Hercules adorned with the PLVS VLTR[A] motto. Obverse PHILIP[PUS] V D[EI] G[RATIA] HISPAN[IARUM] ET IND[IARUM] REX "Philip V, by the Grace of God, King of the Spains and the Indies" Displays the arms of Castile and León with Granada in base and an inescutcheon of Anjou.

Silver dollar of Ferdinand VI of Spain, 1753 Reverse VTRAQVE VNUM M[EXICO] 1753 M "Both (are) one, Mexico [City Mint], 1753." Displays two hemispheres of a world map, crowned between the Pillars of Hercules adorned with the PLVS VLT[R]A motto. Obverse FERD[INA]ND[US] VI D[EI] G[RATIA] HISPAN[IARUM] ET IND[IARUM] REX "Ferdinand VI, by the Grace of God, King of the Spains and the Indies" Displays the arms of Castile and León with Granada in base and an inescutcheon of Anjou.

Silver dollar of Charles III of Spain, 1776 Obverse CAROLUS III DEI GRATIA 1776 "Charles III by the Grace of God, 1776" Right profile of Charles III in toga with laurel wreath Reverse HISPAN[IARUM] ET IND[IARUM] REX M[EXICO] 8 R[EALES] F M "King of the Spains and the Indies, Mexico [City Mint], 8 reales" Crowned Spanish arms between the Pillars of Hercules adorned with PLVS VLTRA motto

Silver dollar of King Charles IV of Spain, 1806 Obverse CAROLUS IIII DEI GRATIA 1806 "Charles IV by the Grace of God, 1806." Right profile of Charles IV in soldier's dress with laurel wreath. It was under the reign of this monarch that the United States Mint began the U.S. silver dollar in 1794. Reverse HISPAN[IARUM] ET IND[IARUM] REX M[EXICO] 8 R[EALES] T H"King of the Spains and the Indies, Mexico [City Mint], 8 Reales." Crowned Spanish coat of arms between the Pillars of Hercules adorned with PLVS VLTRA motto

Silver dollar of Ferdinand VII of Spain, 1821 Obverse FERDIN[ANDUS] VII DEI GRATIA 1821"Ferdinand VII by the Grace of God, 1821." Right profile of Ferdinand VII with cloak and laurel wreath Reverse HISPAN[IARUM] ET IND[IARUM] REX M[EXICO] 8 R[EALES] I I"King of the Spains and the Indies, Mexico [City Mint], 8 reales." Crowned Spanish coat of arms between the Pillars of Hercules adorned with PLVS VLTRA motto

The Spanish dollar, also known as the piece of eight (in Spanish: Real de a ocho, Dólar, Peso duro, Peso fuerte or Peso), is a silver coin of approximately 38 mm (1.5 in) diameter worth eight Spanish reales. It was minted in the Spanish Empire following a monetary reform in 1497. It was widely used as the first 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.^[1]

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.^[2][3][4] Aside from the U.S. dollar, several other currencies, such as the Canadian dollar, the Japanese yen, the Chinese yuan, the Philippine peso, and several currencies in the rest of the Americas, were initially based on the Spanish dollar and other 8-real coins.^[5] Diverse theories link the origin of the "$" symbol to the columns and stripes that appear on one side of the Spanish dollar.^[6]

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. Of these, "peso" remains the name of the official currency in Argentina, Chile, Colombia, Cuba, Dominican Republic, Mexico, Philippines, and Uruguay.

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.