The economic history of the United Kingdom relates the economic development in the British state from the absorption of Wales into the Kingdom of England after 1535 to the modern United Kingdom of Great Britain and Northern Ireland of the early 21st century. Scotland, England, and Wales shared a monarch from 1601 but their economies were run separately until they were unified in the 1707 Act of Union. Ireland was incorporated in the United Kingdom economy between 1800 and 1922; from 1922 the Irish Free State (the modern Republic of Ireland) became independent and set its own economic policy.