On 1 January 1999 a new currency, the euro, was launched and a new institution, the Eurosystem,
took over responsibility for the single monetary policy in the euro area, which is one of the largest developed economic areas in the world.
However, the euro area is not only large but it is also a heterogeneous economic area since it comprises individual countries with different economic and financial structures. With regards to the size and the heterogeneity of the euro area, the creation of a single currency and a single monetary policy has faced extraordinary challenges, among them the design of suitable instruments and procedures, i.e. of a suitable operational framework, for the conduct of monetary policy.