The United Kingdom is an island country situated off the northwestern coast of mainland Europe. It encompasses the entire island of Great Britain, housing England, Wales, and Scotland, along with the northern part of the island of Ireland. The term “Britain” is occasionally used to denote the United Kingdom as a whole. The capital is London, a global hub for commerce, finance, and culture. Major cities include Birmingham, Liverpool, and Manchester in England; Belfast and Londonderry in Northern Ireland; Edinburgh and Glasgow in Scotland; and Swansea and Cardiff in Wales.
The roots of the United Kingdom trace back to the time of the Anglo-Saxon king Athelstan in the early 10th century CE. Athelstan secured the allegiance of neighboring Celtic kingdoms, marking the consolidation of rule over territories that were previously shared among many kings. Over the ensuing centuries, further conquests expanded English dominion. The Acts of Union in 1536 and 1542 formally united Wales with England. In 1707, Scotland, ruled from London since 1603, was formally joined with England and Wales, forming the United Kingdom of Great Britain. The term “British” began to be used to refer to all the kingdom’s peoples during this period. Ireland, brought under English control in the 1600s, was formally united with Great Britain through the Act of Union in 1800. In 1922, the Republic of Ireland gained independence, while Northern Ireland, comprising six of Ulster’s nine counties, remained part of the United Kingdom.
The relationship between these constituent states and England has been marked by controversy, open rebellion, and warfare at times. While tensions relaxed in the late 20th century with the introduction of devolved assemblies in Northern Ireland, Scotland, and Wales, challenges persisted. Despite the establishment of power-sharing assemblies after referenda in both Northern Ireland and the Republic of Ireland, relations between unionists (favoring continued British sovereignty over Northern Ireland) and nationalists (favoring unification with the Republic of Ireland) remained tense into the 21st century.