The United Kingdom of Great Britain and Ireland was established on 1 January 1801 under the terms of the Acts of Union 1800, by which the nominally separate kingdoms of Great Britain and Ireland were united. In 1922, twenty-six of thirty-two counties of Ireland seceded to form the Irish Free State, later becoming the Republic of Ireland. Northern Ireland remained part of the United Kingdom, and the state was consequently renamed the "United Kingdom of Great Britain and Northern Ireland".