On the outbreak of the First World War, it was used as a recruiting centre and training depot for troops being sent to France. However, by 1916 it was sparsely occupied by a garrison of about 100 men.
Unknown to the barracks' garrison, just down the South Circular Road the Third Battalion of the Irish Volunteers, Dublin Brigade was preparing for insurrection in April of that year. They assembled on Easter Sunday at nearby Emerald Square and proceeded to the South Dublin Union, now St James Hospital, where they occupied that complex as part of the Easter Rising. Two young Volunteers were sent to make sure that troops inside Wellington Barracks were not being mobilised against them but reported nothing out of the ordinary.
Inside the barracks, the meagre garrison, augmented by passing British troops, had initially just six rifles between them. Fortunately for them, the complex was not attacked during the week's fighting, though an army patrol dispatched up towards Wexford Street was fired on, resulting in one dead and one wounded. The barracks also came under sniper fire.
Subsequently, as peaceful conditions returned to Dublin, the Barracks resumed its normal role. However, by 1919, conflict was again in the air, as the Volunteers, now called the Irish Republican Army or IRA, prepared for guerrilla warfare against British troops in the Irish capital. An IRA quartermaster named Kit Farrell, with the aid of a sympathetic Irish serviceman stationed in the barracks, Edward Handley, bought and smuggled over 100 rifles and thousands of rounds of ammunition out of the barracks - swimming the weapons across the Grand Canal at the rear of the complex by night in small batches.
From the spring of 1921 to July of that year, the garrison was also harassed by small scale guerrilla attacks on their patrols. IRA statements record at least three ambushes of patrols from Wellington in the immediate vicinity of the barracks.
Images courtesy of the National Library of Ireland and Harper's Weekly