Fighting in a Mine: Was it the Ultimate Deed of Arms?

By Steven Muhlberger

The dark and confined space of a medieval mine was not a place where you wanted to fight a battle. Yet, doing so carried a special significance for knights and men-at-arms.

In the Later Middle Ages much attention was paid to men-at-arms who fought and raided the villages, towns and camps of their opponents. The prizes and victories won in various conflicts not only wealth but reputation. An increase in reputation made the person who gained it a more desirable commander, who might be more likely to win battles or successfully pursue a siege, which would also benefit the men-at-arms he led. These men-at-arms were known for their individual participation in deeds of arms – whether jousts, tournaments, or various actions of warfare.


It was a competition for fame, against both “companions” and enemies.  In this largely informal game, achieving deeds of arms was open to interpretation. What was the most impressive deed of arms, in the eyes of knights, squires and plain men of arms? Men either witnessed these feats, or heard stories of the deeds, and based their judgements on their personal experiences or the consensus of those with whom they discussed the issue at hand.

Let me cast my vote for “fighting in a mine.” There is some dramatic and convincing evidence that men who took part in such a dangerous contest won great respect of others from their own profession.


During the Hundred Years War between the kings of England and France, castles and fortifications were the key to controlling territories disputed between them. There were various ways to take or defend fortifications, but one of the most common tactics was building a tunnel (a mine) to collapse a wall. Defenders built countermines against the attacker’s mine.

When mines and countermines met, the result was a very dangerous type of combat.  Whoever was at the mineface was fighting in short, dark, airless conditions.  I have gone down into pre-modern mines in Cornwall, UK and Sudbury, Ontario and I found it hard to imagine an armoured man doing anything in such cramped conditions. We know from scholarly investigations of Crecy and Agincourt that suffocation in full armour was a real danger even in the open air.

A drawing from Bellafortis depicting a castle collapsing as a mine is on fire. Besançon BM MS.1360 fol. 68

Yet some of these professional warriors willingly exposed themselves to the risk of not only fighting in the mine but taking the lead. These included the highest ranking among them, including King Henry V.

During his campaigns in  France, Henry fought in several mines. To have a reigning king lead the way into a mine was surely very impressive, but the reaction of the observers was interesting too. In one case an appeal to the laws of arms concerning fighting in a mine prevented Henry from gaining something he dearly wanted – the execution of Arnaud Guilhelm, Lord of Barbazan. In 1420, Barbazan was captured during the siege of Melun. He had been involved in one of the great crimes of the aristocratic world, the murder of Jean sans Peur, Duke of Burgundy, and Henry like many others considered Barbazon an infamous traitor. The king would have executed Barbazon except a herald, who happened to be Barbazon’s brother-in-law, objected that Barbazon was Henry’s brother-in-arms and brothers-in-arms should not kill each other if one captured the other. Why were they brothers? Because they had fought each other in a mine during the siege, in other words, had participated in a great deed of arms.  The appeal to their shared chivalry saved Barbazon’s life. It is not the only case where the status attached to fighting in a mine transformed a military situation. Half a century earlier Louis the Good, Duke of Bourbon, and an opponent used the prestige of fighting in a mine to their advantage.


The duke was cleaning up the countryside of Poitou, retaking fortifications from the English brigands who used them as bases to pillage the peasantry. The French lords of the region had proved ineffective, even timid, so the duke decided to take things into his own hands. He brought some of his best men to besiege the castle of Vertueil, to join the Poitevin lords already there, and had a mine built. When the mine met the countermine made by the garrison, the duke made a bold use of it. Accompanied only by a single man-at-arms and wearing no distinctive harness, he marched up to the outside end of the mine and had his companion ask whether the garrison had a knight interested in fighting him. There were no knights inside but the challenge was accepted by the castle’s second in command, a squire named  Regnaud de Montferrand. The duke and the squire advanced into the mine and began fighting energetically. The duke’s men began cheering “Bourbon! Bourbon! Notre Dame!”

Regnaud soon figured out that something was going on. He asked the duke’s companion if this indeed was the real Duke of Bourbon. When the answer was “yes” he had to think fast. People in his position – mediocre in rank, associated with no legitimate authority – were frequently condemned for their plundering and hanged. But since the duke had already shown Regnaud a certain amount of respect Regnaud dared to make an offer: he would surrender the castle if the duke would knight him. The duke was impressed and made complimentary noises about Regnault. He agreed to the surrender on one condition – that the next day every warrior who wished to could fight in the mine.  The Chronicle of the Good Duke indicates that the Duke’s military household was a tough, ambitious band anxious to make names for themselves. The next day there was indeed fighting in the mine. The duke’s men were immediately treated as heroes to the point that the reluctant Poitevin lords decided they could contribute to the duke’s anti-brigand campaign—but only if they were led by “those who fought in the mine.”

A number of interesting points could be made from these episodes. Fighting man-on-man in various formats was one of the ways that a man-at-arms could win fame and become an exemplar of chivalry. But as Maurice Keen said long ago “fighting in a mine did have a special significance according to the laws of chivalry.” I concur.


And if you don’t believe me, go to Sudbury, put on a medieval helmet, and take a tour of one of those old mines. Then see what you think!

Steven Muhlberger, before he retired from Nipissing University, studied and taught Late Antiquity, the history of democracy, Islamic history, and chivalry. His most recent scholarly works include The Chronicle of the Good Duke Louis II Bourbon published by Freelance Academy Press.

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A mine underneath a castle during a siege, depicted in the Manesse Codex. © UB Heidelberg, Cod. Pal. germ. 848, fol. 229v