History of the formation of the United Kingdom Kingdom of England (which included Wales and controlled Ireland) and the Kingdom of Scotland. The once independent Principality of Wales fell under the control of English monarchs from the Statute of Rhuddlan in 1284. The Union of Crowns in 1603, the accidental consequence of a royal marriage one hundred years earlier, united the kingdoms in a personal union, though full political union in the form of the Kingdom of Great Britain required a Treaty of Union in 1706 and Acts of Union in 1707 (to ratify the Treaty). The Act of Union 1800 united the Kingdom of Great Britain with
Unionism in England in various stages of the Union Flag, which forms the flag of the United Kingdom. The larger part of Ireland left the United Kingdom in 1922, however the separation of Ireland which originally occurred under the Government of Ireland Act 1920 was upheld by the British Government and the Unionist-controlled devolved Parliament of Northern Ireland, and chose to remain within the state today, which is now officially termed the United Kingdom of Great Britain and Northern Ireland. The 300th anniversary of the union of Scotland and England was marked in 2007. In England, support for the Union has traditionally been