1985

The Schengen Agreement
An agreement was signed between Belgium , Luxembourg , the Netherlands , Germany and France on the gradual abolition of checks at their common borders to support the free movement of persons. This agreement was signed in the Luxembourg town of Schengen.

1990

The Schengen Convention was signed, implementing the Schengen Agreement of 1985.

1990

Italy joins

1991

Spain and Portugal join

1992

Greece joins

1995

The Schengen Convention came into effect, abolishing the internal borders of the signatory states and creating a single external border where immigration checks for the Schengen area are carried out in accordance with a single set of rules. 'Compensatory' measures (such as improved police and judicial co-operation, and the Schengen Information System), were put into place.
Austria joins

1996

Denmark , Finland and Sweden join
Whilst not members of the EU, Iceland and Norway become members of Schengen due to prior agreements with the Nordic countries on border controls.

1999

The Treaty of Amsterdam- Entry into force (Treaty was agreed on June 1997 but didn't come into force until May 1999)
The Schengen Acquis was integrated into the European Union by means of a Protocol to the Treaty of Amsterdam. The Protocol also specified that the United Kingdom and Ireland could take part in all or part of the Schengen arrangements, subject to unanimous approval by the Council.

2000

The UK 's application for ‘partial yet significant' participation in Schengen was approved.

2002

Ireland 's application for partial participation in Schengen was approved.