The name Irish Republican Army (IRA ) was used by the military wing of the Fenian Brotherhood of America, a revolutionary movement founded in 1858 in the industrial cities of the north-eastern United States.
That Irish Republican Army came to global prominence in the 19th century with several attempted invasions of British-controlled Canada between the years 1866 and 1871. Staged by rival factions of the Fenian organisation the main objective was the establishment of an “Irish Republic in Exile” on the North America continent by the exploiting the simmering post-Civil War tensions between Washington and London (senior members of the White House and US Congress initially encouraged the Fenian plans).
Though the strategy failed the abbreviation “IRA” was added to the lexicon of Irish and international politics.
Some fifty years later when the Fenian sister-movement in Ireland, the Irish Republican Brotherhood (IRB), orchestrated an insurrection against British colonial rule in the country it did so by coalescing several existing paramilitary organisations under one banner. These were the Irish Volunteers, Irish Citizen Army and Hibernian Rifles which in the Easter Rising of 1916 assumed the collective title of the “Army of the Irish Republic” or, as you may have guessed, the “Irish Republican Army”. The IRA was thus reborn for a new generation and a new century.