The Irish state came into being in 1916 as the 32 county Irish Republic. In 1922 having seceded from the United Kingdom under the Anglo-Irish Treaty, it became the Irish Free State. It comprised 32 counties until 6 counties under the control of Unionists, opted out. The 1937 constitution renamed the 'Southern Ireland' state "Ireland". In 1949 only 26 counties explicitly became a republic under the terms of the Republic of Ireland Act 1948, definitively ending its tenuous membership of the British Commonwealth. In 1973 the 'Southern Ireland' State joined the European Communities.