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
Treaty of Union Treaty of Union The Treaty of Union is the name usually now given to the agreement which led to the creation of the new state of Great Britain, stating that England (which already included Wales) and Scotland were to be "United into One Kingdom by the Name of Great Britain", At the time it was more often referred to as the Articles of Union. The details of the Treaty were agreed on 22 July 1706, and separate Acts of Union were then passed by the parliaments of England and Scotland to put the agreed Articles into effect. The political union