Euro coins in the context of "European Central Bank"

The euro convergence criteria (also known as the Maastricht criteria) are the criteria European Union member states are required to meet to enter the third stage of the Economic and Monetary Union (EMU) and adopt the euro as their currency. The four main criteria, which actually comprise five criteria as the "fiscal criterion" consists of both a "debt criterion" and a "deficit criterion", are based on Article 140 (ex article 121.1) of the Treaty on the Functioning of the European Union.

Full EMU membership is only open to EU member states. However, the European microstates of Andorra, Monaco, San Marino and the Vatican City, which are not members of the EU, have signed monetary agreements with the EU which allow them officially to adopt the euro and issue their own variant of euro coins. These states had all previously used one of the eurozone currencies replaced by the euro, or a currency pegged to one of them. These states are not members of the eurozone and do not get a seat in the European Central Bank (ECB) or the Eurogroup.

The Eurosystem is the monetary authority of the eurozone, the collective of European Union member states that have adopted the euro as their sole official currency. The European Central Bank (ECB) has, under Article 16 of its Statute, the exclusive right to authorise the issuance of euro banknotes. Member states can issue euro coins, but the amount must be authorised by the ECB beforehand.

The Eurosystem consists of the ECB and the national central banks (NCB) of the 20 member states that are part of the eurozone. The national central banks apply the monetary policy of the ECB. The primary objective of the Eurosystem is price stability. Secondary objectives are financial stability and financial integration. The mission statement of the Eurosystem says that the ECB and the national central banks jointly contribute to achieving the objectives.

Banknotes of the euro, the common currency of the eurozone (euro area members), have been in circulation since the first series (also called ES1) was issued in 2002. They are issued by the national central banks of the Eurosystem or the European Central Bank. The euro was established in 1999, but "for the first three years it was an invisible currency, used for accounting purposes only, e.g. in electronic payments". In 2002, notes and coins began to circulate. The euro rapidly took over from the former national currencies and slowly expanded around the European Union.

Denominations of the notes range from €5 to €500 and, unlike euro coins, the design is identical across the whole of the eurozone, although they are issued and printed in various member states. The euro banknotes are pure cotton fibre, which improves their durability as well as giving the banknotes a distinctive feel. They have a variety of color schemes and measure from 120 by 62 millimetres (4.7 in × 2.4 in) to 160 by 82 millimetres (6.3 in × 3.2 in) (first series) and from 120 by 62 millimetres (4.7 in × 2.4 in) to 153 by 77 millimetres (6.0 in × 3.0 in) (second series). The euro notes contain many complex security features such as watermarks, invisible ink characteristics, holograms, optically variable inks and microprinting that document their authenticity. While euro coins have a national side indicating the country of issue (although not necessarily of minting), euro notes lack this. Instead, this information is shown by the first character of each note's serial number.

The 1 euro cent coin (€0.01) has a value of one hundredth of a euro and is composed of copper-covered steel. It is the lowest-value coin in the Eurozone; the next lowest are the 2 and 5 euro cent coins. All euro coins have a common reverse and a country-specific (national) obverse. The coin has been used since 2002 and was not redesigned in 2007 as was the case with the higher-value coins.

€2 commemorative coins are special euro coins that have been minted and issued by member states of the eurozone since 2004 as legal tender in all eurozone member states.

€2 coins are the only denomination intended for circulation that may be issued as commemorative coins. Only the national obverse sides of the commemorative coins differ; the common reverse sides do not. The coins typically commemorate the anniversaries of historical events or current events of special importance.