According to the Constitution of Ireland, the names of the Irish state are Ireland (English) and Éire (Irish). From 1922 to 1937, its legal name was the Irish Free State. The state has jurisdiction over almost five-sixths of the island of Ireland. The rest of the island is Northern Ireland, a part of the United Kingdom. Consequently, other formal and informal names have been (and are) used when it is necessary to distinguish between the territory of the state and the island as a whole. In 1948 it adopted the term Republic of Ireland as the official description of the state, without changing the constitutional names.