The Belgian, French, German, Luxembourg and Dutch government signed the Schengen Agreement on 14 June 1985. Under the agreement, the five countries would phase out common border controls. The Schengen Agreement includes two separate agreements that were ratified in 1985 and 1990 respectively. Between them, they abolished border controls and greatly facilitated transit through Europe. The two individual agreements stipulate that, although switzerland is not a member of the EU, switzerland, because of its position at the heart of Europe, maintains strong economic and social relations with many Schengen states and is part of the European Free Trade Association (EFTA) with Iceland, Norway and Liechtenstein (other third countries within the Schengen area). Switzerland became an integral part of the Schengen area after signing the agreement on 26 October 2004 and beginning to implement it on 12 December 2008. Now that the Schengen Agreement is part of the Community acquis, it has lost to the EU Member States the status of a treaty which could only be amended in accordance with its terms. Instead, changes are made in accordance with the EU`s legislative procedure under the EU treaties.  Ratification by the former signatory states is not necessary to amend or repeal all or part of the previous Schengen acquis.  Acts setting out the conditions for accession to the Schengen area are now adopted by a majority of the EU`s legislative bodies. The new EU Member States do not sign the Schengen Agreement as such, but are required to implement the Schengen rules within the framework of existing EU legislation, which any new entrant must accept. [Citation required] Originally, the Schengen treaties and the rules adopted between them were officially independent of the EEC and its successor, the European Union (EU). In 1999, the Treaty of Amsterdam incorporated them into EU law, which codified Schengen into EU law and also introduced opt-outs for Ireland and the Kingdom, the latter having taken place since its withdrawal from the EU.
EU Member States that do not yet have an opt-out and have not yet joined the Schengen area are legally obliged to do so if they meet the technical requirements. Although it is linked to EU legislation, several third countries are present in this region after signing the agreement. This means that Schengen Member States that were not part of the EU have few formally binding options to influence the development and development of Schengen rules; their options are effectively reduced to approval or exit from the agreement.