The construction of Europe originated in the Treaty of Rome, signed in 1957 by Germany (FRG), Belgium, France, Italy, Luxemburg and the Netherlands. It involved economic cooperation based on a common market. In 1922, the Maastricht Treaty implemented the institutional framework of the European Union and created an economic and monetary union. The last modification was completed by the Lisbon Treaty in 2009. Following several phases of expansion, the Union now has 27 members.