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
International status and usage of the euro those in the eurozone, do not participate in the European Central Bank or the Euro Group. Its international usage has also grown as a trading currency, acting as an economic or political alternative to using the United States dollar. Its increasing usage in this sense has led to its becoming the only significant challenger to the US dollar as the world's main reserve currency. Several European microstates outside the EU have adopted the euro as their currency. For EU sanctioning of this adoption, a monetary agreement must be concluded. Prior to the launch of the euro, agreements were reached with