A year later, this real July 12 battle was just as decisive as the Boyne ...

Although Orangemen celebrate the Battle of the Boyne on July 12, the battle which actually took place on that date was Aughrim, a year after the Boyne in 1691.

While the Boyne remains the largest and most famous military confrontation on this island, ‘Aughrim’s dread disaster’ was the bloodiest battle in Irish history.

At the Boyne two kings – William III and James II – fought on the banks of an Irish river for three kingdoms – England, Scotland and Ireland – but no kings were present at Aughrim. Largely, because of this, Aughrim rarely receives the attention it merits. Many people don’t even know where Aughrim is. Yet, a strong case can be made for regarding Aughrim rather than the Boyne as the decisive battle of the Williamite wars.

At the Boyne, the Williamites had a numerical advantage over the Jacobites but at Aughrim the two armies were evenly matched numerically – each having 20,000 men. Qualitatively, the Williamite army had a decided advantage and they had the additional advantage of having 25 cannon to the Jacobites’ 10.

Aughrim was the product of the determination of the Marquis de Saint-Ruth, the Jacobite commander, to fight. Arguably, it was an unnecessary battle, which owed much to Saint-Ruth’s wounded pride and his desire to stamp his authority on his army.

It was also the last great pitched battle in Irish history.

At the Boyne, James II had lost Ireland east of the Shannon. However, the Jacobite army remained virtually intact. Even before the Boyne the preferred strategy of James’s French allies was to hold the line of the Shannon. This strategy was now put into effect. However, on June 30 Godard van Reede de Ginkel, a Dutchman and the new Williamite commander, succeeded in breaching the Shannon line with the capture of the Jacobite stronghold of Athlone while Saint-Ruth, the new Jacobite commander, looked on helplessly.

The loss of Athlone represented a major setback to the Jacobites and was the source of dissension within the Jacobite leadership. Tyrconnell, James’s Lord Deputy, urged Saint-Ruth to fall back on Limerick. Sarsfield, the charismatic hero of the engagement at Ballyneety, advocated guerrilla warfare.

Saint-Ruth felt humiliated by the loss of Athlone and was anxious to redeem his reputation. Thus, Saint-Ruth chose to ignore the wiser counsels of both Tyrconnell and Sarsfield and make a stand at Kilcommodan or Aughrim Hill, five miles south-west of Ballinasloe, County Galway.

Saint-Ruth’s choice of battlefield had much to commend it. The hill rose to some 400 feet and was two miles long, running from the ruins of Aughrim castle to Kilcommodan church. In front of the hill lay a bog. Occupying the position on July 8, Saint-Ruth had four days before the battle to make preparations. He positioned his army behind the marsh, a position which served his army very well in the first hour or two of fighting on July 12.

On the Sunday morning before the battle Saint-Ruth, a religious fanatic with a track record as a ruthless persecutor of the Huguenots, is believed to have psyched up his troops by telling them that they were engaged in a crusade against heresy.

The course of the battle was complex and accounts are frequently contradictory. Ginkel’s army attacked the Jacobites at 5.00 pm and encountered stiff and determined resistance. To meet pressure on his right wing Saint-Ruth moved infantry and cavalry to reinforce his position. Seeing this manoeuvre Ginkel took advantage of the situation to mount an attack on Saint-Ruth’s left. The Williamites gained a footing on the lowest slope of the hill but were overrun by Jacobite cavalry and infantry, so much so that the Jacobites pursued the Williamites as far as their cannon beyond the bog.

However, the Jacobites failed to take away the Williamite cannon. Ostensibly, the battle was going Saint-Ruth’s way and he prematurely boasted: ‘The day is ours, my children’ but the Williamites were able to repulse the Jacobites with chevaux-de-frise (a defensive obstacle created by fixing sword or other blades into a beam or log and fulfilling much the same function as barbed wire).

However, Ginkel was not the sort of man to acquiesce in Saint-Ruth’s verdict and persisted with the battle.

Eventually, the Jacobites found themselves being outflanked by Williamite cavalry who had discovered and crossed a causeway to their left. Tradition alleges that a treacherous Jacobite officer revealed the existence of causeway to the Williamites. Saint-Ruth was changing the disposition of his forces to meet the new situation when he was decapitated by a cannon ball.

Saint-Ruth’s failure to acquaint his senior officers with his plan of battle meant they did not know what his intentions were. De Tessé, Saint-Ruth’s second-in-command, was thrice wounded and left the battlefield without appointing a successor. Sarsfield had no authority to take over. All he could do was cover the Jacobite retreat as best he could. Without leadership chaos set in and the Jacobite army disintegrated.

Further confusion resulted from the fact that when the Jacobites started to run out of ammunition, boxes of English ammunition were opened but they found that English musket balls were too big for French flintlocks.

Without leadership and the wherewithal to fight, Jacobite soldiers had little option other than to retreat.

At the Boyne, William of Orange did not pursue his retreating enemy closely. At Aughrim, both the Williamite cavalry and infantry pursued the enemy with vigour. They showed them little mercy: the humane William probably would not have countenanced such slaughter.

‘Aughrim’s dread disaster’ was the bloodiest battle in Irish history. On the Jacobite side one general, three major-generals, seven brigadiers, 22 colonels, 17 lieutenant-colonels, and over 7,000 other ranks were killed. A further 450 Jacobites were taken prisoner.

By comparison, Williamite losses probably did not exceed 700 killed and 1,000 wounded.

Williamite commanders paid generous tribute to the military prowess of their defeated opponents. The Duke of Würtemburg, the commander of the Danish troops in William’s service, wrote that the Jacobites had resisted much more vigorously than had been expected and that the outcome of the battle had been in doubt for two hours.

Ginkel won an impressive victory. If the outcome of the war was not inevitable after the Battle of the Boyne, it most emphatically was after Aughrim.

What would have happened if the Jacobites had won? Could they have won back what they had lost? This is exceedingly doubtful because William would simply have committed whatever resources would have been necessary to win.

However, if instead of fighting at Aughrim the Jacobites had simply retreated to Limerick (as Tyrconnell had wisely suggested) they might well have obtained better terms than they did at the Treaty of Limerick.