Why was the European Union founded?

The European Union was founded by Belgium, France, Germany, Italy, Luxembourg and the Netherland in 1957. The goal of the European Union was to unite the national economies in Europe and to prevent future wars between the members states. To integrate the European economies further a single currency, the Euro, was introduced in 1999. Noways the European Union consists of 27 members, of which 20 have the Euro as official currency.