Irish Unionist Alliance - Ulster Unionism

Ulster Unionism

The party was replaced in Ulster by the Ulster Unionist Party from the start of the twentieth century. In Ulster, other reasons for unionism included the industrial growth of Belfast after 1850 that depended on the British Empire, and a fear of Rome Rule, the worry about an overly Catholic-dominated new Irish parliament. In the tense period between the Parliament Act 1911 and the Home Rule Act 1914, the fear arose that an Irish civil war would occur between nationalists in the south and west and the Ulster unionists, who created their own paramilitary group, the "Ulster Volunteers".

From 1914 to the formal partition of Ireland in 1920-21, the Ulster Unionists relied upon their local electoral majority in what became Northern Ireland. Under the 1921 Anglo-Irish Treaty Northern Ireland became a part of the Irish Free State from its creation on 6 December 1922; and the Northern Irish parliament voted to leave the Free State two days later.