Euro cheques, electronic transfers, banking, etc.) at midnight on 1 January 1999, when the national currencies of participating countries (the eurozone) ceased to exist independently. Their exchange rates were locked at fixed rates against each other. The euro thus became the successor to the European Currency Unit (ECU). The notes and coins for the old currencies, however, continued to be used as legal tender until new euro notes and coins were introduced on 1 January 2002. The changeover period during which the former currencies' notes and coins were exchanged for those of the euro lasted about two months, until 28 February
Currency substitution financial assets denominated in a foreign currency. It can also occur as a gradual conversion to full currency substitution, for example, Argentina and Peru were both in the process of converting to the U.S. dollar during the 1990s. "Dollarization", when referring to currency substitution, does not necessarily involve use of the United States dollar. The currencies that have been used as substitutes have been the US dollar, the euro, and the Australian dollar. After the gold standard was abandoned at the outbreak of World War I and the Bretton Woods Conference following World War II, some countries sought exchange rate