Ireland and the United Kingdom are both part of the European Union (EU). The Crown Dependencies are not a part of the EU however do participate in certain aspects that were negotiated as a part of the UK's accession to the EU. Neither the United Kingdom or Ireland are part of the Schengen area, that allow passport-free travel between EU members states. However, since the partition of Ireland, an informal free-travel area had existed across the region. In <answer>1997</answer>, this area required formal recognition during the course of negotiations for the Amsterdam Treaty of the European Union and is now known as the Common Travel Area.
When was a free-travel area created betwen Northern Ireland and Ireland?
1997