Euro convergence criteria in the context of "European Central Bank"

The economic and monetary union (EMU) of the European Union is a group of policies aimed at converging the economies of member states of the European Union at three stages.

There are three stages of the EMU, each of which consists of progressively closer economic integration. Only once a state participates in the third stage it is permitted to adopt the euro as its official currency. As such, the third stage is largely synonymous with the eurozone. The euro convergence criteria are the set of requirements that needs to be fulfilled in order for a country to be approved to participate in the third stage. An important element of this is participation for a minimum of two years in the European Exchange Rate Mechanism ("ERM II"), in which candidate currencies demonstrate economic convergence by maintaining limited deviation from their target rate against the euro.

The Treaty on European Union, commonly known as the Maastricht Treaty, is the foundation treaty of the European Union (EU). Concluded in 1992 between the then-twelve member states of the European Communities, it announced "a new stage in the process of European integration" chiefly in provisions for a shared European citizenship, for the eventual introduction of a single currency, and (with less precision) for common foreign and security policies, and a number of changes to the European institutions and their decision-making procedures, not least a strengthening of the powers of the European Parliament and more majority voting on the Council of Ministers. Although these were seen by many to presage a "federal Europe", key areas remained inter-governmental with national governments collectively taking key decisions. This constitutional debate continued through the negotiation of subsequent treaties (see below), culminating in the 2007 Treaty of Lisbon.

In the wake of the Eurozone debt crisis unfolding from 2009, the most enduring reference to the Maastricht Treaty has been to the rules of compliance – the "Maastricht criteria" – for the currency union.