The United Kingdom of Great Britain and Ireland was the formal name of the United Kingdom from 1 January 1801 until 12 April 1927. The United Kingdom was formed by the merger of the Kingdom of Great Britain (itself a merger of the Kingdoms of England and Scotland) and the Kingdom of Ireland. Its name was changed in 1927 after the majority of Ireland left the UK in 1922 and became the sovereign Irish Free State, thus leaving only six counties in the north within the UK.