As an engineer officer, I care passionately about just a few things: castles, engineer buttons, and combined arms breaching. And while there were no engineer buttons at Helm’s Deep – a simple oversight, I’m sure – that engagement encompasses a wide swathe of engineer lessons learned.

Yes, this means we’re delving back into the world of J.R.R. Tolkien, to keep him from getting any well-earned rest by pestering him for military insights from his work of fiction, The Two Towers. Specifically, from the engagement between the coalition forces of Rohan and the hybrid threat of Saruman’s army.

And for those of us who care about such things, this is not the actual battle of Helm’s Deep, because that place referred to the ravine behind the fortress. Properly, it is called the Battle of the Hornburg. But since people can’t read maps properly and then some of those people make movies, it has become known as the Battle of Helm’s Deep. And you wonder why historians drink.

This engagement is quite different from that at Minas Tirith which was handled in a previous post. While that was a multi-domain operation with a wide array of forces, this engagement is in essence a light infantry – or even cavalry – defense of key terrain, opposing the most rudimentary of combined arms breaches. That was NTC, this is JRTC. The problem statement becomes, can a light cavalry force fight as heavy infantry inside obstacle belts and still preserve enough combat power to retain the initiative once the enemy attack has culminated?

It all boils down to overmatch and trading space for time, which are two pieces of the modern battlefield that might be very familiar for some readers, especially the ones wearing the obnoxious hats and spurs.

Let’s go ahead and break this down as we always do, looking at it through the lens of our warfighting functions, just like the good staff officers that we are. It’s like a Pavlovian response – say warfighter and all the officers start prattling off.

Now, the situation was thus, if you recall: the nation-state of Rohan had been brought out of neutrality due to the depredations of the upstart region of Isengard, a former protectorate which had now been subverted by Sauron of Mordor. Rohan itself had been infiltrated through a well-placed adviser to King Theoden by the name of Grima Wormtongue, an agent working on behalf of Saruman the White – the ruler in Isengard and a puppet of Sauron. As attacks by Saruman’s insurgent forces began to rise, Grima used his skill in information operations to confuse the situation at Rohan’s court, seed discord among the key leaders, and prevent any serious offensive action against the insurgency.

This was broken by the arrival of Gandalf, who proceeded to undo Grima’s network, restoring functionality to Rohan’s political system. Because the king was not only the civil ruler but also the wartime commander, this also freed up Rohan’s military forces for action. Some small elements of cavalry were already operating against the king’s orders in an effort to disrupt Saruman’s orcs as they attacked civilian targets. Gandalf provided Theoden a full intelligence update, which included the news that a force of about 10,000 orcs and discontented men from Dunland was expected to move in open warfare against Rohan.

Seeing that the insurgency had gotten out of his control and was moving to large scale combat operations, Theoden decided to mass as many of his forces as he could at the Hornburg fortress in order to delay the enemy until further forces could be mustered. This was done under the advisement of Gandalf, who was not only proficient in intelligence but also operations.

Rohan’s force structure consisted of light and medium cavalry formations, specializing in wide area maneuver, reconnaissance, and skirmishing. It contained no air assets, no artillery, and no heavy infantry formations. Troopers could fight on foot as infantry when the case called for it. And because the Riddermark operated on a levy system, they did not have a large standing army once open hostilities began. This is what drove Theoden to a defensive posture, where he would be sacrificing his mobility in favor of survivability.

Theoden’s objective was to survive long enough to seize the initiative from the enemy; failing that, it was to destroy as much of their force as possible, preventing them from mounting another effective offensive operation.

Command and Control

From inside the Hornburg, Theoden and his leadership could count approximately 2,000 troopers who had arrived before the enemy sealed off the main avenue of approach to the fortress. They were facing a force five times their number. Therefore, good mission command would have to be vital for their operation. Unfortunately, Gandalf violated mission command by not providing the most clear instructions that he could have. Leaving his three comrades – Aragorn, Legolas, and Gimli – with Theoden, Gandalf disappeared into the fields on an unnamed mission. His only guidance was to wait for 24 hours, but his GOTWA lacked any other specifics. Leadership in battle would come primarily from Aragorn, whose understanding of ground tactics and his ability to display presence were a major morale boost for Rohan.

While Gandalf was unclear in his intentions, he was just carrying out Theoden’s commander’s intent, however: marshaling all available Riders of Rohan. As the battle began and enemy forces concentrated on the Hornburg, Gandalf rapidly built up combat power from among the scattered riders of Rohan, gaining an additional 1,000 dismounted troopers.

In addition, Gandalf built a coalition with the Ents, ancient guardians of the trees. Saruman had attacked the trees around Orthanc in addition to the people, and so the Ents had grievances with him as well. Utilizing his keen understanding of the situation, Gandalf cemented a relationship between Rohan and the Ents, formulated a two-pronged strategy to destroy the forces of Isengard, and moved quickly to relieve the Hornburg. Due to his swift reading of the situation, Gandalf was able to build combat power through liaison networks and would bring victory out of defeat. He remains the most proficient ideal of the staff officer.

Movement and Maneuver

Now, the forces of Rohan specialized in maneuver. Which is ironic, since they could no longer find any way of maneuvering inside their three obstacle belts. For them, they could only see themselves be maneuvered upon by the 10,000 orcs and human irregulars arrayed against them. The enemy force was all light, medium, or heavy infantry, with some light artillery to be employed against the obstacles. The enemy did not maneuver, either, opting for mass over maneuver. In wave assaults, they breached Helm’s Dike – the outer work – first. The first line of defenders conducted an orderly rear passage of lines into the main walls.

From there, the enemy worked to breach the second obstacle, the fortress’s main walls. Working in a storm, they used the rain and cloud cover for obscuration, although it did not prevent small arms fire from the walls of the fortress. Aragorn and Eomer – the key battlefield leader for Rohan – identified where the enemy’s point of breach would be, which was at the gate using a battering ram. They allowed the enemy breaching force to advance past their support by fire until they were isolated in the breach, and then Aragorn and Eomer led a sortie into the breach to destroy the enemy’s engineer assets, which they accomplished. However, the two leaders did not identify the enemy’s redundant breaching asset and assumed that the main threat to the obstacle belt had been destroyed.

Frustrated, the enemy then began to attempt multiple points of breach by scaling the walls with ladders. While this dispersed the defenders and caused some amount of confusion, it was also not the most efficient way of breaching the obstacle. Although there were small breaches, they were quickly sealed, all at massive cost of life to the enemy.

Enemy recon forces finally identified a bypass – a culvert under the main wall. The fixing force rushing through the culvert, enveloping the friendly force from the rear. Aragorn, Legolas – sniper qualified – , and Gimli led the counterattack that sealed this breach. Gimli, a graduate of Engineer Captain’s Career Course, oversaw obstacle reinforcement efforts around the culvert to seal the breach. However, the enemy assault force struck the culvert again, seeing it as the weakest point in the obstacle belt. This time they used an in-stride explosive breach which reduced the obstacle and allowed the exploitation force to follow through the gap and begin outflanking friendly positions.

From here, Aragorn and Eomer led two groups of defenders to their secondary fighting positions: Aragorn into the Burg itself, with Theoden and most of his heavy cavalry, and Eomer into the Glittering Caves with some dismounted troops. Aragorn conducted a leader’s recon at dawn, where he identified that friendly forces had lost all ability to maneuver but that the enemy had grown over-confident in victory and were losing momentum.

At dawn, Theoden initiated a PSYOP fires operation (see the Fires section for more information) which halted enemy offensive action. This was followed by a strong counterattack by his heavy cavalry which drove into the enemy mass and seized the initiative in the engagement. Seeing this attack, Eomer led a similar assault on the flank from the caves. Using speed, surprise, and audacity, this attack drove the enemy back to the walls of the fortress and beyond. The two pronged assault retained momentum but seemed doomed to fail in the face of heavy enemy numbers.

Intelligence

Task Force Gandalf, now consisting of 1,000 infantry and innumerable Huorns – a living forest – had concealed its existence from Saruman’s intelligence operations via speed and surprise. Ents had attacked Isengard itself, pinning Saruman into the tower of Orthanc which tied all his attention to that one location. Unable to gather new information, Saruman lost control of the battle and was unable to direct its course.

TF Gandalf timed its assault at the Hornburg to coincide with the cavalry counterattack. Thus caught between three assaulting elements, one of which resembled a walking forest, the enemy defense disintegrated. The Dunlendings – men who had joined with Saruman out of grievances against Rohan – were so terrified that they dropped their weapons and surrendered. Aragorn, Eomer, and Gandalf directed their ground forces against the orcs, pushing them towards the Huorns. Denied any avenue of retreat save this, the orcs fled into the wood never to be seen again. The intelligence coup brought off by Gandalf was now complete. The enemy land force was effectively annihilated.

Fires

Neither side brought any significant direct or indirect fires assets to the engagement, minus some siege weaponry that was more effective for suppressing fire than anything else. However, friendly forces did retain the Horn of Helm. This was a PSYOP weapon that could be sounded in Helm’s Deep and was a significant psychological deterrent to enemy attackers. When this was sounded at the coming of dawn, it checked the enemy advance, causing them to be caught off-balance when the counterattack happened. Non-lethal fires thus played a significant role in the effectiveness of the defense of the Hornburg.

Sustainment

Defenders in the Hornburg and Glittering Caves could count on plenty of Class I and Class V that had been built up over the years. Lack of Class IV meant that obstacles could not be repaired in a timely manner and that the task force engineer Gimli would have to improvise. And with no good medical facilities, wounded defenders could really only rely on combat lifesavers among the force.

The force also lacked good weapons and armor for the civilian auxiliaries pressed into the defense of the Hornburg. Many soldiers lacked properly fitting body armor or effective weapons. With minimal repair facilities, soldiers had to make do with what they had. Gimli himself notched his axe and had to wait until after the battle for it to be properly repaired. Forward support elements of armorers could have alleviated some of this strain on the operational force.

In his role as task force personnel officer, Gandalf quickly realized that force regeneration was going to be his main priority. He conducted personnel accountability operations throughout Rohan during the night of the battle, collecting small units and coordinating their movement to the forward line of troops under the direction of Erkenbrand, the surviving light infantry commander. Task organizing this force proved crucial for the eventual counterattack and is a model for all S-1 officers everywhere.

Protection

The Hornburg consisted of three distinctive obstacle belts which also served as protective fighting positions for defenders: the outer dike, the main wall, and the fortress itself. Built into a mountainside, the position could not be outflanked and would have to be taken by frontal assault. Historically, it had never fallen to an enemy attacking from the outside.

Weaknesses in the position had been identified early in the engagement by Theoden, who had asked his task force engineer to look to improving some of the defensive positions. But like so many task force engineers, Gimli was not given the time or the assets needed to bring the positions into the proper state of repair as he would have liked, given his professional reputation in the matter. Gimli instead relied on his secondary role of fighting as an infantryman to seal many of the breaches. This brought great credit upon himself, Task Force Rohan, and the Corps of Engineers.

Summary

In conclusion, the forces of Rohan were able to mount a successful defensive operation at the Hornburg through mutually supporting positions, clearly defined fallback criteria, and sound leadership using mission command. This enabled a quick transition to the offense. Synchronization was the key to success in the end, as fires, maneuver, and intelligence combined to destroy the enemy assault on the Hornburg. This resounding victory enabled Rohan to protect its forces from further attacks from Saruman, which were themselves a part of Sauron’s shaping operations against Gondor. Free from Saruman’s hybrid warfare attacks, Rohan was able to rapidly mobilize its remaining forces and project power all the way to Minas Tirith. Their arrival on the battlefield there played a key role in defeating the army of the Witch King and allowed the Captains of the West to seize the initiative and begin a campaign into Mordor.

My continued apologies to Tolkien who surely just wants to rest in peace.

About the Author: Angry Staff Officer is an Army engineer officer who is adrift in a sea of doctrine and staff operations and uses writing as a means to retain his sanity. He also collaborates on a podcast with Adin Dobkin entitled War Stories, which examines key moments in the history of warfare.

This article by The Angry Staff Officer originally appeared on The Angry Staff Officer in 2019.

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The Wakandan Civil War: A Profile in State Reconstruction

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Image: NineLine Films/The Two Towers/YouTube Screenshot