The European Exchange Rate Mechanism froze the exchange rates of the legacy currencies in the eurozone, establishing the value of the euro.

The European Exchange Rate Mechanism (ERM II) is a system introduced by the European Economic Community on 1 January 1999 alongside the introduction of a single currency, the euro as part of the European Monetary System (EMS), to reduce exchange rate variability and achieve monetary stability in Europe.

In finance, an exchange rate is the rate at which one currency will be exchanged for another currency. Currencies are most commonly national currencies, but may be sub-national as in the case of Hong Kong or supra-national as in the case of the euro.

The euro area, commonly called the eurozone (EZ), is a currency union of 20 member states of the European Union (EU) that have adopted the euro (€) as their primary currency and sole legal tender, and have thus fully implemented EMU policies.

The euro is the official currency of 20 of the 27 member states of the European Union. This group of states is officially known as the euro area or, more commonly, the eurozone. The euro is divided into 100 euro cents.