The history of the United Kingdom as a unified sovereign state began in 1707 with the political union of the kingdoms of England and Scotland, into a united kingdom called Great Britain. Of this new state the historian Simon Schama said "What began as a hostile merger would end in a full partnership in the most powerful going concern in the world... it was one of the most astonishing transformations in European history." A further Act of Union in 1800 added the Kingdom of Ireland to create the United Kingdom of Great Britain and Ireland.