The Eurosystem is the monetary authority of the Eurozone. It is a system of central banks consisting of the European Central Bank (it decides the monetary policy) and the central banks of the member states of the European Union whose currency is the euro (their function is to apply the monetary policy decided by the ECB). The European System of Central Banks should have been the monetary authority of the Eurozone, however as not all the member states of the European Union adopted the euro, the Eurosystem, which is identical to the ESCB except that it does not include the central banks whose countries have not joined the euro, had to be created.
