The Parliament of Ireland and the Parliament of Great Britain also merged with one another because of the Act of Union 1800. In 1801, Great Britain and Ireland started to be one kingdom: the United Kingdom of Great Britain and Ireland. This happened on 1 January 1801, while George III was king. The Irish Free State left the United Kingdom in 1922, and in 1927, the UK's name changed to be the United Kingdom of Great Britain and Northern Ireland. 