The Benelux countries (Belgium, Luxembourg and the Netherlands) had already set up a common passport area in 1970. In 1984, following protests by truck drivers over delays at border crossings between France and Germany, the two countries signed a bilateral agreement to remove controls along their shared border. The concept of free movement was originally intended to allow the European labour force to move freely and settle in any EU Member State, but the removal of border controls within the UNION remained behind it. The breakthrough was achieved in 1985, when cooperation between the various governments (i.e. Belgium, France, Germany, Luxembourg and the Netherlands) led to the signing of an agreement on the phasing out of common border controls in Schengen (a small village in Luxembourg); In 1990, the convention was signed. The developments initiated by the Schengen Agreement were incorporated into the EU`s legal framework with the Treaty of Amsterdam in 1999. Today, the Schengen area comprises 26 EU Member States, with the exception of Ireland and the United Kingdom (opt-out clause), Bulgaria, Croatia, Cyprus and Romania, as well as four non-EU states – Iceland, Norway, Switzerland and Liechtenstein. Bulgaria and Romania are currently in the process of joining the Schengen area. Indeed, the Schengen Agreement paved the way for the release of the Schengen visa. Although this is not part of the original provisions of the agreement, the top 15 countries need only a visa for all. The Schengen visa may allow non-EU members to travel freely to the countries participating in the programme.
However, the United Kingdom and Ireland are involved in certain aspects of Schengen, including the Schengen Information System. Iceland and Norway also signed an agreement with the EU in 1999 to continue their participation in the Schengen area. The Treaty of Amsterdam, signed in 1997, officially integrated Schengen into the Framework of the European Union as a Schengen acquis. The Schengen acquis includes the 1985 Schengen Agreement, the 1990 Schengen Agreement, as well as various decisions and agreements adopted during the implementation of Schengen. When the Treaty of Amsterdam came into force in 1999, the decision-making power of Schengen was submitted to the EU Council of Ministers. In December 1996, two non-EU states, Norway and Iceland, signed an association agreement with the countries that signed the Schengen accession agreement. Although this agreement never entered into force, the two countries were part of the Schengen area following similar agreements with the EU.  The Schengen Agreement itself was not signed by non-EU states.
 In 2009, Switzerland officially concluded its accession to the Schengen area by adopting an association agreement by referendum in 2005.  Several Schengen countries – Belgium, Germany, Spain, France, Luxembourg, the Netherlands and Austria – signed an agreement with The “Schengen III” in May 2005. The agreement would establish closer cooperation between countries in the prevention and fight against terrorism and crime. In another case, the visa application resulting from the Schengen agreements corresponds to any visa procedure.