There have been 12 monarchs of the Kingdom of Great Britain and the United Kingdom (see Monarchy of the United Kingdom) since the merger of the Kingdom of England and the Kingdom of Scotland on 1 May 1707. England and Scotland had been in personal union under the House of Stuart since 24 March 1603. On 1 January 1801, Great Britain merged with the Kingdom of Ireland (also previously in personal union with Great Britain) to form the United Kingdom of Great Britain and Ireland. After most of Ireland left the union on 6 December 1922, its name was amended on 12 April 1927 to the United Kingdom of Great Britain and Northern Ireland.
Timeline of British monarchs