The European Monetary Unit (ECU) was a unit of account used by the European Union from 1979 to 1998. It was replaced by the Euro in 1999 and was used as a currency for international transactions. The ECU was based on a basket of European currencies and was designed to reduce exchange rate fluctuations between member countries. It was also used to measure the value of the European Currency Unit (ECU), which was the predecessor to the Euro.