Kings & Queens of Britain
There have been 12 monarchs of the Kingdom of Great Britain & the United Kingdom since the merger of the Kingdom of England & the Kingdom of Scotland on 1 May 1707.
England & Scotland had been in personal union under the House of Stuart since 24 March 1603 (James VI & I's reign).
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 & 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 & Northern Ireland.
Since 8 March 1702 Anne had been Queen of England, Scotland & Ireland, & so became Queen of Great Britain upon the Union of England & Scotland. I will cover the monarchs prior to 1707 elsewhere. This is just a short introduction into each monarch.
The House of Stuart (1707–1714); House of Hanover (1714–1901); Houses of Saxe-Coburg and Gotha (1901–1917) and Windsor (from 1917)