The ECSC was regarded as a success - so national governments decided to expand this co-operation to other areas in 1957 when 'the Six' signed the Treaty of Rome. This built on the work of the ECSC and created two more international bodies; the European Economic Community (EEC) and the European Atomic Energy Community (Euratom), to work alongside the ECSC.
In 1965 a treaty was signed that drew together the separate elements of the previous treaties. As the most influential body of the three was the EEC, this became the name for the group.
In 1973 the EEC expanded to include Denmark, Ireland and the UK. Britain held a referendum on its membership in 1975 in which the British public voted to stay in the EEC.
In 1979 Europeans voted in the first direct elections to the European Parliament.
At the Milan Summit in 1985 the European leaders decided to celebrate Europe Day annually on May 9th.
Spain and Portugal joined in 1986. In this year the first European passports were introduced and the European flag was raised to the tune of Beethoven's 9th Symphony, the European anthem. The Single European Act also came into force to remove artificial trade barriers between states so that goods, capital, services and people could move, live and work freely and without restriction in any of the Member countries.
The most important negotiations about the EEC's roles and responsibilities took place in 1991 at a meeting in Maastricht, Netherlands. The meeting which created the Treaty of the European Union - and brought all the different organisations into a single framework called the EU.
- created a timetable for economic and monetary union (the euro).
- introduced policies covering 'social' issues such as workers rights and health and safety.
- started the process of enabling Eastern European countries to join the EU.
On January 1st 1993 all trade barriers were removed; one of the most important steps in creating the Single Market.
The Treaty of Amsterdam was signed in 1997. It updated the Maastricht Treaty to prepare for the enlargement of the EU to include Eastern European countries and strengthened the 'Social Chapter' which includes law on employment and discrimination.
In 1998 the EU took its first formal steps towards eastwards enlargement by opening formal negotiations with Hungary, Poland, Estonia, the Czech Republic, Slovenia and Cyprus. A year later, Romania, Slovakia, Latvia, Lithuania, Bulgaria and Malta opened membership negotiations. Turkey has also applied for membership, but formal membership negotiations have not yet started.
In January 1999, eleven countries met the rules for adoption of the euro as their official currency on 1st January 2000. Greece met the criteria two years later. On 1 January 2002, euro notes and coins replaced the national currencies in those twelve countries. The UK, Sweden and Denmark did not adopt the euro in 2002.
The EU is now the largest political and economic partnership in the world accounting for 38% of free trade. With free movement of goods, services and people for its 375 million citizens (rising to over 500 million after the next wave of enlargement), the EU provides opportunities for everyone.