The legal texts which established the European System of Central Banks (ESCB) - the Maastricht Treaty and the Statute of the ESCB of 1993 - were written on the assumption that all EU Member States will adopt the euro and that therefore the ESCB will conduct all the tasks involved in the single currency. However, until all EU countries have introduced the euro, it is the "Eurosystem" which is the key actor. The term "Eurosystem" covers the ECB and the national central banks of those EU Member States that have adopted the euro. Until now an unofficial term, it is mentioned for the first time in the Lisbon Treaty (Article 282 of the Treaty on the Functioning of the European Union).
The Eurosystem as the central banking system of the euro area comprises:
The Eurosystem is thus a sub-set of the ESCB. Since the ECB's policy decisions, such as on monetary policy, naturally apply only to the euro area countries, it is in reality the Eurosystem, which, as a team, carries out the central bank functions for the euro area. In doing so, the ECB and the NCBs jointly contribute to attaining the common goals of the Eurosystem.
There are three main reasons for having a system of central banking in Europe:
For the mission statement of the Eurosystem, see www.ecb.europa.eu/ecb/orga/escb/html/mission_eurosys.en.html.
OR.002 01/12European Central Bank