The Spanish dollar (also known as the piece of eight, the real de a ocho or the eight-real coin) is a silver coin, worth eight reales, that was minted in the Spanish Empire after a Spanish currency reform in 1497. Its purpose was to correspond to the German thaler. It was the coin upon which the US dollar was based, and it remained legal tender in the United States until the Coinage Act of 1857 discontinued the practice. Because it was widely used in Europe, the Americas, and the Far East, it became the first world currency by the late 18th century. Many existing currencies, such as the Canadian dollar, United States dollar, and the Chinese yuan, as well as currencies in Latin America and the Philippine peso, were initially based on the Spanish dollar and other 8-reales coins.