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 the United Kingdom single Parliament of Great Britain at Westminster as well as a customs and monetary union. However, England and Scotland remained separate legal jurisdictions. In 1801, the Acts of Union 1800 united the Kingdom of Great Britain with the Kingdom of Ireland, through two similar independent acts of the Parliament of Great Britain and the Parliament of Ireland. This created the United Kingdom of Great Britain and Ireland on a similar basis to how England and Scotland had been united a century earlier. A campaign to repeal the Union in Ireland began immediately. A series of efforts in the late 19th