The European Union’s legal basis for operating its institutions and laws are a series of international treaties. The first of these was the Treaty of Rome, signed in 1957 by the first six countries: Germany, France, Italy, Belgium, Luxembourg and the Netherlands. It was not until 1973 that Great Britain joined, along with the Republic of Ireland and Denmark.
The EU gained new powers and responsibilities with the Single European Act in 1986, while the 1992 Treaty of Maastricht set out a path for the creation of the euro currency. The EU was adapted by the Treaties of Amsterdam (1997) and Nice (2001) and the 2007 Treaty of Lisbon was the last major adjustment of the EU’s structure.
In response to the problems caused by the credit crunch and recession, which harmed the euro countries, many EU members also signed the Fiscal Stability Treaty in 2012.