What happened at the Battle of the Boyne

11 Jul 2019 Nick Garbutt    Last updated: 11 Jul 2019

The battle site showing the curve in the river: Pic: Wikicommons

James and his forces were doomed. The Boyne was the only defensible barrier between the Williamite army and Dublin but the ground he had chosen to fight on was not.


And fortune favoured William. The day before the fight he went to the river bank to inspect the enemy’s position. A cannon ball grazed his shoulder. He was inches from death. At Aughrim a year later the Jacobite General de Ruth was decapitated by a cannon ball, precipitating the rout that turned potential Jacobite victory into total defeat. Good luck is as important as good generalship in war.   

It all began in Ulster. King James needed to secure it if he was to get to Edinburgh and reclaim his ancestral crown as James VII of Scotland, raise a new army, and march on London. King William had to use it as a bridgehead if he was to bring his army to Ireland and send James, both his uncle and father-in-law, back to France.

That’s why Derry was besieged, defended and, ultimately relieved on August 1 1689 after 15 gruelling weeks.

It would surely have fallen if the mercenary General Conrad von Rosen, Marshall of Ireland had had his way. Von Rosen was an exponent of the darkest arts of war. He was a Lutheran from what is now Latvia who had signed up for the French Army and converted to Catholicism just before Protestants were expelled from France.

When he took over the siege he ordered troops to gather up local Protestants from around the city and drove them to the city walls. This was a tactic used by the English warlord Henry V in the siege of Rouen in 1418 where non combatants were trapped between the city and the besieging army – and the defenders were faced with the dilemma of letting them in and running out of food, or else watching them die outside the walls.

James was appalled. He ordered von Rosen to stop and had him removed back to France the following Spring. The defenders held out, and less than two weeks later another soldier of fortune, this time the German Duke of Schomberg landed with 20,000 men near Bangor.

Schomberg was one of the greatest generals of his day, and a veteran of the Thirty Years War. He had risen even higher in the French service – to Marshall of France – he was also a Protestant but unlike von Rosen chose to join William rather than convert.

After a short siege Carrickfergus fell to Schomberg and his army marched south. It comprised around 10,000 raw English recruits bolstered by victorious forces from the battles in Ulster together with an array of veterans of different nationalities from the European wars.

Von Rosen wanted to burn all the crops in his path, kill the livestock, burn the towns and villages, abandon Dublin and retreat to west of the Shannon, letting nature do the rest to the Williamite army. He was ignored, but he had also underestimated the extreme difficulty of marching through Ireland in those days.

1689 was a miserable, wet Irish summer, supplies started to diminish, animals were slaughtered but no salt could be found to preserve the meat. There was no bread. Dysentery (known then as the red flux) and typhus struck. By the time Schomberg reached Dundalk his army was in a miserable state, with many dead and many more unable to fight.

On the morning of October 1 1689 James’s forces caught up with him. His army of 20,000 took to the field in full battle array, the Royal Standard was raised. There was a brief stand-off as James’s generals squabbled amongst themselves and then the Jacobites marched away.

One hundred years later British General Sir Henry Keating wrote that James would have destroyed the Williamites if he had attacked, he had “Schomberg in a cul-de-sac, his retreat cut off, his army wasting by sickness”.  

To some military historians this was a terrible blunder that cost James Ireland and any hopes of restoring his crown. By the time Schomberg got back to Lisburn for the winter he had just 7,000 men.

Yet it was more complicated than that. The Irish army was still in the process of being purged of Protestants by the Earl of Tyrconnell. The resulting force had received little or no training and were poorly armed – some infantry had scythes instead of pikes and whilst the Jacobites had old matchlock muskets the Williamite troops had the new-fangled flintlocks. After the disastrous performance in Ulster James believed they needed further training.

Then there were the French. The war in Ireland was part of a more general European conflict- the Nine Years War, one where William was getting the upper hand. Their brief was not so much to win, but to prolong the conflict, keeping William distracted from events in mainland Europe.

And so, the following year, William, frustrated with Schomberg’s lack of progress, arrived in person. Both sides were reinforced, the Jacobites by 7,000 French veterans. William mustered an army of 36,000, comprising English, Irish, Dutch, Danish, German and French Hugenots. Both armies fought under the Royal Standard and wore a multitude of uniforms. To add to the confusion both English and Irish troops on either side wore red. To distinguish themselves Williamites wore sprigs of green in their hats, Jacobites, pieces of white paper.

William marched south, James fell back to the Boyne. This was the only practicable course open to him if he was to defend Dublin – it was the sole military obstacle. He chose the only site he could, at Oldbridge, with his left flank towards Slane and his right at Drogheda. But he and his generals failed to recognise the glaring weakness of his position.

His defending army was in the loop of a river – one which is fordable in many places. Military strategists have long argued that the very best way to force a river crossing is to trap opposing armies in just such a position. They can be attacked from the side, and are vulnerable to being wiped out if you can get behind them and assault from the rear.

So, as the armies bedded down for the night before battle, James was in a perilous position and also significantly outnumbered – with 25,000 men 1,500 of which were in Drogheda.

William called a council of war. Schomberg wanted to split the army with one smaller force assaulting Oldbridge from the front. He wanted to detach most of the army, march during the night across the ford at Rosnaree and surprise James from the flank and the rear. It was the classic solution and held out the prospect of obliterating Jacobite forces. He was opposed by the Dutch commander Count Solms who wanted a single attack from the front. William vaccilated, eventually agreeing a compromise, involving a smaller force marching to Rosnaree.

The delay was his biggest blunder. By the time the flanking troops set off it was 5am and already light. The Jacobites could see them through the early morning mist and James sent half his army to defend the position, including all the crack French troops. The Williamites forded the river and the two opposing sides faced one another across a boggy strip of land. Neither side made a move for the rest of the battle.

James may have protected his flank and line of retreat but it left the rest of his army outnumbered by three to one. And by 10am, led by the crack Dutch Guards, William launched his frontal attack at Oldbridge. The river was waist deep at this point and when they reached the other side they were charged by the Irish Guards. What followed was ferocious. The Irish lost around 150 men, the Dutch about the same but all the time were being reinforced by more troops crossing the river.

Then the Irish cavalry swept down the hill. They were led by Tyrconnell, a 60 year-old veteran of the Cromwellian wars who was all but crippled from old wounds. They broke the lines of the Dutch Guards and fell on the French Hugenots who had come up to reinforce them.

Seeing that his troops were in serious trouble Marshall Schomberg rode to rally them. He was slashed twice with a sabre and then shot in the back of the neck. Frederick Schomberg was 75 years old. George Walker, who was Governor of Derry during the siege was killed trying to go to Schomberg’s aid.

The fighting at Oldbridge went on for two hours. At around 11 am a further 12,000 troops started to cross the river at a place the Jacobites believed was unfordable. The water was so deep that some of the troops were up to their necks: the Irish tried to repel them but the more troops they sent to that position the further the Dutch Guards were able to push them back.

Just after noon William himself crossed with his cavalry and the game was up. The Jacobite infantry rallied a few times before fleeing over the bodies of their comrades and through the wreckage of their camps and abandoned baggage. The cavalry fought on, protecting their retreat, suffering great losses. The Duke of Berwick who was James’s natural son ended the battle with just 16 unwounded men out of his 200 Life Guards.

The divided Jacobite army was reunited at Duleek. Only half of it had fought at all. Of the elite French troops brought in to stiffen James’ army only six men were lost.

It is estimated that around 1,000 Jacobites died at the Boyne. Williamite losses are put at around 500. More than twice as many more will have been wounded. These were not especially high casualties for a battle at this period. At the Battle Of Aughrim the following year there were 7,000 killed.

Within three weeks James was back in France. The war went on for another year, but the Boyne secured Dublin for William and removed his rival from the scene. Aughrim was the last, most bloody battle in the war, this was the decisive one.

In a wider context the Boyne established the Ascendancy and is celebrated for that by some to this day. But there was more too that would echo down through the years. It also marked the last time that Irish rebels would march under the Royal Standard of an English King. The monarch they had fought for was renamed Seamus an chaca – James the shit.



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