The Great Rebellion began when thousands of south Leinster United Irishmen turned out to confront government forces. The intense period of open warfare which ensued during that summer claimed tens of thousands of lives and devastated the infrastructure and economy of many counties.
Risings occurred in almost every sector and Wexford, Wicklow, Kildare, Antrim, Down, Longford, Meath and Mayo witnessed largescale pitched battles.
No part of the country was untouched by the pivotal events of the summer of 1798 in which Ireland became the most critical front of the worldwide French war that began six years earlier. Indeed, the French directly intervened in the west in August 1798 and made two further efforts that year to make good their commitment to the republican cause of the United Irishmen.
The government's extensive intelligence sources ensured that it knew a massive uprising was imminent in May 1798 but neither threats nor inducements delivered concrete evidence of United Irish strategy. The reasons for this were twofold.
In the first instance, Castle agents failed to penetrate the close-knit inner circle of the United Irish leadership in Dublin. The decision-making command in the capital was free from spies. Thomas Reynolds, whose defection occasioned the arrest of the bulk of the Leinster Directory of which he was a member in March, was then isolated by imprisonment with those he had betrayed.
Top-level agents Leonard McNally, Nicholas Mageean and "Lord Downshire's friend" Samuel Turner, enjoyed only peripheral contact with the key players in the rebel organisation and were largely reliant on information channelled through the compromised Ulster Directory.
Second, a rebellion strategy was not actually agreed by the fractured leadership until about a week before it was proposed to put it into execution. Discarded and amended draft plans, however, filtered down the rebel chain of command throughout the spring of 1798 and reached the ears of informers.
These garbled and contradictory communications sent to the Castle served only to confuse the executive and may well have hindered their assessment of the situation.
Informers indicated the existence of a threat to the army reserve camp at Loughlinstown while others pointed to a citybased coup d'etat plan envisaging attacks on such targets as the Bank of Ireland, the Houses of Parliament at College Green and the artillery barracks at Island Bridge.
In the final analysis, no reliable picture of insurgent intentions could be or was obtained in Dublin until two hours before the moment of truth.
Of course, an organisation as vast as the United Irishmen, which boasted 280,000 members in 1798, could never be impervious to hostile elements or truly secret in its workings. Its general intentions were public knowledge, predictable and often published in the reports of county and provincial committees to their constituents.
Garrison towns did not need to be told that attack was likely if local rebels mobilised in force. Arms raids and assassinations were constant reminders of a smouldering low-intensity struggle as well as harbingers of further upheaval. Even more ominous signs of impending unrest appeared in the days before May 23rd when mysterious fires were sighted in the Dublin mountains and sizeable arms shipments were intercepted on their way to the country.
The only real questions for government supporters in the advent of the revolt were whether the vacillating rebels would await the arrival of the French and if the largely Catholic Irish militia which comprised the bulk of the defence forces was reliable.
The militia was heavily infiltrated and looked to by the United Irishmen for the arms, training and professional manpower considered necessary to stiffen massed cadres of pikemen. The consensus of informed observers in early May 1798 was that the French were no longer essential to rebel plans while the militia, reinforced in 1797 by staunch Scottish and English fencible regiments, was reasonably dependable.
The sophisticated revolutionary cell structure developed by the United Irishmen provided their activists with limited protection but could not be relied upon to withstand the terror elicited by the full rigour of martial law.
In April/May 1798 details of their principal personnel and county level objectives were obtained by such means as random flogging of suspects in Kildare and Wicklow, pitchcapping in north Wexford and houseburning in Cork.
The extremity of the counter-insurgent policy and the panoply of special powers with which it was underpinned appalled British liberals and signalled the sense of crisis which pervaded government offices in Dublin Castle. It was, however, effective. In some sectors the flow of intelligence produced by state terror overwhelmed the magistracy, who momentarily believed that the backbone of sedition had been crushed.
Wicklow's commander, Brig Gen Joseph Hardy, declared on May 22nd, 1798, that information was coming in "faster than it can be taken down".
Matters appeared much less hopeful in west Wicklow on the 23rd where a conservative magistrate claimed that the surviving rebel leaders were absent in the capital attending the "day expected for rising there", oblivious to the fact that he was writing on that very day.
Another loyalist authority ascertained from a Dublin radical that two heavily armed emissaries had been sent from the capital to tell the men of Wicklow and Kildare to rise "immediately".
Republicans had suffered the severe setback on the 19th when their main strategist, Lord Edward Fitzgerald, was captured in Thomas Street. Less important but demoralisng were the arrests of Henry and John Sheares, also high-ranking figures, two days later. Daily arrests tightened the noose around the fugitive city leadership in which command devolved on the coterie attached to Samuel Neilson. The militant and capable Belfast man was indefatigable in his efforts to finalise preparations for war.
The crux of the plan was for the citymen to seize the capital on the night of May 23rd, 1798, aided by reinforcements from the counties adjoining Dublin, where diversionary attacks would take place. An outer ring of Leinster counties would then rise to hamper, if not prevent, the movement of military reinforcements from the provinces to the city.
Great confidence was placed in the numerous Ulster organisations which had partially recovered from the trauma of dragooning of 1797. Another perceived strongpoint was Munster, where the Cork-centred conspiracy was also very strong but major garrisons and army camps throughout the country were to be assaulted at the earliest opportunity.
Rural United Irishmen were advised that the non-arrival of the regular mails from the capital would confirm that the citymen, upon whom all else was contingent, had acted as planned. Dublin rebel Watty Cox recalled that around 9 p.m. on May 23rd "a very busy and extensive range of preparation took place in Dublin and its vicinity", including a briefing by senior figures held in Abbey Street.
Neilson had previously given the final order to the city and county colonels in a meeting at Church Lane. He was captured shortly afterwards when reconnoitring Newgate prison for a mooted rescue attempt on the senior United Irishmen inside.
The Dubliners gathered their forces and weapons and moved towards prearranged objectives and mobilisation points. It was intended to mount a wave of attacks at 10 p.m.but this was hastily cancelled when it was discovered that the yeomanry had just occupied the predesignated rallying sites of Smithfield, Newmarket and the few other open locations in the metropolis.
Robert Ross claimed: "Nine o'clock at night, government get a second information. Drums beat to arms. A rising in mass immediately expected. The army and yeomanry alerted spirited and in force, and the rising prevented."
Unable to mass in numbers sufficient to overcome an alerted garrison, thousands of city rebels melted away into the lanes of the south city abandoning their weapons as they fled. An estimated 10,000 weapons were recovered at first light on the 24th, and 500 pikes were found in Bridgefoot Street. The plan for an irresistible uprising emanating from Dublin lay in tatters but the Rebellion of 1798 had begun.
Street fighting, ambushes and skirmishes killed hundreds that night in Naas, Prosperous, Ballymore Eustace, Fox-and-Geese, Rathfarnham, Kilcullen and Fingal. Scores of other concentrations materialised across Leinster, where battle was not immediately joined.
By dawn tens of thousands of United Irishmen menaced all the major approaches to the capital and initiated a fresh wave of assaults in Wicklow, Kildare, Carlow, Meath and Dublin. The rising spread quickly to the north, west and south but the failure to halt all the interprovincial mailcoaches and other communications difficulties ensured that the first news the vast majority of United Irishmen heard was of the collapse of the central plank of their strategy.
There would be no general insurrection. Indeed, within 24 hours of the start of the rebellion, it was clear to the military that an ad hoc, reactionary and piecemeal campaign was in the offing. Few would have believed that a formidable challenge to the state was in train which would claim at least 30,000 lives in six weeks.
Ruan O'Donnell is a lecturer in history at St Patrick's College, Drumcondra, Dublin and also teaches in UCD. His publications include a revised and expanded edition of Luke Cullen's Insurgent Wicklow (Kestrel Books, 1998) and The Rebellion in Wicklow, 1798, published by Irish Academic Press.