The European Central Bank
The European Central Bank (ECB) is the only central bank governed by supranational constitutional law. As such, it is not only the most important institution of the Economic and Monetary Union (EMU), but it also marks a new stage in the history of central banking in general. Historically, the tasks and functions of the ECB have reflected the different stages of development of the EMU. The basic principles governing its function were set out in Maastricht, reflecting the interests and ideas about Europe’s economic constitution prevailing at that time. The sovereign debt crisis that hit Europe in 2010 was the second defining moment for the ECB after Maastricht. It posited the ECB–like the rest of the EMU–to challenges that some of the drafters of the Maastricht Treaty had not fully anticipated. These new challenges led to the adoption of novel instruments and the further clarification of fundamental rules and principles. Most important of these developments was the entrustment of the ECB with a new task, banking supervision, and the adoption of unconventional measures, which proved necessary to fulfil its monetary-policy mandate. Ultimately, not only did the ECB withstand the crisis but it emerged as a protagonist in securing the unity and integrity of the EMU.