History of the British Isles

The British Isles have witnessed intermittent periods of competition and cooperation between the people that occupy the various parts of Great Britain, the Isle of Man, Ireland, the Bailiwick of Guernsey, the Bailiwick of Jersey and the smaller adjacent islands.

Today, the British Isles contain two sovereign states: the Republic of Ireland and the United Kingdom. There are also three Crown dependencies: Guernsey, Jersey and the Isle of Man. The United Kingdom comprises England, Northern Ireland, Scotland, and Wales, each country having its own history, with all but Northern Ireland having been independent states at one point. The history of the formation of the United Kingdom is very complex.

The British monarch was head of state of all of the countries of the British Isles from the Union of the Crowns in 1603 until the enactment of the Republic of Ireland Act in 1949, although the term "British Isles" was not used in 1603. Additionally, since the independence of most of Ireland, historians of the region often avoid the term British Isles due to the complexity of relations between the peoples of the archipelago (see: Terminology of the British Isles).