The Unsung Heroes of Medieval Warfare: How Clerks Shaped Armies

By Steven Muhlberger

Medieval warfare often evokes images of knights and their weapons, yet a significant but less celebrated group played a crucial role: the clerks. Let’s examine how they managed administration and documentation, supporting military operations behind the scenes. 

We often think of medieval warfare in terms of warriors and their characteristic weapons. Jim Bradbury is a good example. In his The Medieval Siege he devotes a solid chapter to medieval siege weapons including mines and miners, the use of ladders for scaling walls, siege weapons, etc.  Gunpowder weapons get appropriate coverage. This chapter gives us a good idea of the variety of specialists that might make up a well-organized army.


There is a significant military group that doesn’t often get the recognition that it deserves, whether we are talking about numbers or the practicalities of war. They did not usually wield weapons but were more likely to use pens.  They were the ‘clerks’.

You may well ask why clerks should be seen as an important part of medieval armies. ‘Clerk’ is not a simple word, even though clerks or clergy were everywhere doing things required of, or forbidden to ordinary Christians (Think ‘clergyman’).  The clergy were a distinct group who lived by their own laws and subject to their own hierarchy of officers (i.e. bishops, abbots, parish priests). They also wielded authority over the laity though the extent of that authority was controversial.


A cleric was also a person who could read and write in Latin. The clergy were distinguished by their ability to use the language of earlier imperial regimes, more recent ecclesiastical legislation and in particular the Bible. The same skills could be used for more mundane uses: A lord who wanted a good record of his properties would likely have a charter written either in Latin or, as time went on, in the local vernacular. Clerks as people used to writing were well equipped to use the vernacular for practical, literary or religious purposes.

Clerks produced or read a large variety of documents including those needed for warfare. Clerks went everywhere warriors were – on battlefields, on the march, and at sieges. They also took care of administration which was necessary for organizing effective military action. This despite the official position of the church on warfare.

Indeed the teachings were ambiguous. One of the earliest ‘Church Fathers’, St. Augustine of Hippo, systematized the teachings on war in his encyclopedic  The City of God. For those who followed Augustine, there were causes where the Church could justify war or other forms of coercion and even rally the warriors (milites) to fight the enemies of the faith. Clerks routinely and sincerely criticized warriors as men of blood who were often motivated by plunder and revenge, but the clergy often worked with them, too. Two famous cases of such cooperation are Pope Gregory VII’s proposed expedition to the East (1087) and the more famous call by Urban II for what became the First Crusade (1096).

Pope Urban II preaching the First Crusade in the presence of King Philip I before the assembly. An illustration from the Grand Chronicle of France, illuminated by Jean Fouquet, Tours, c. 1455-1460

Long before these dramatic incidents, Christian lords and rulers both cooperated with the clergy and used them to do the more routine written work that was necessary to run an army.


If a warrior ran into a clerk as he crossed the siege camp, that clerk was less likely to be a pope, a bishop or a major abbot, than a working clerk, using his literate skills to contribute to the war effort. Let’s consider as an example of a cleric enmeshed in warfare, John, the author of the History of William Marshal. The History (written in 1226) is one of the best sources we have for the reigns in England of Henry II, Richard I, John, and the career of the Young King Henry, all seen through the perspective of William and his household, who quite naturally regarded William who had just recently died as the strongest, most loyal, and most trustworthy actor in the turbulent period of King John’s reign just past. We have no details about John the author but we can see that he was a man who had a sophisticated appreciation of what made good history. He not only used a variety of sources but indicated their reliability, and when he felt that his information was defective, he apologized for the lack.

John had a talent for verse in Old French, the vernacular of the Anglo-French aristocracy and the language most likely to reach the audience he clearly wanted to please. The stories he wanted to tell were largely those that presented William as the greatest warrior anyone had ever heard of. One commonly cited story shows the Marshal taking the bridles of rival knights in tournament, a tactic that allowed one tourneyer to capture another. The Marshal’s skill at this offered as an example of his bold behaviour in battle and tournament. John the author says:

My witness to this is John of Earley
To whom, I understand, the bridles were handed over.
Since those receiving the bridles tell the story,
It must be believed and treated
As a fact both heard and seen.


There are many other examples of John reporting or reconstructing events or speeches made by the leaders of the various conflicts, especially the civil war (1215-7) in which William led a good part of the king’s faction. John took such stories in their raw form, reshaped them in verse and preserved them in writing.

If oral sources did much to shape John’s History, John also used documentary sources and showed other people using clerical skills. One striking example shows us the key role of clerks in war and politics: on the verge of an earlier civil war:

Richard [Lionheart] had had drawn up –
At least two hundred sets of letters or more
And that nobody had ever seen him so desperate
To seek out his men
Throughout his land
As well as those who had joined  his camp
And supported his cause.

Note here that this is a 12th-century Anglo-French prince who had to rely on his clerks or he would have no army!


We’ve seen that clerks compiled and recorded information that could describe an army or a tournament. Sometimes they could do no better than rough estimates. For instance, the French fleet led by Eustace the Monk

Their pilot and commander…
The truth of the matter is that they had
At least three hundred ships in their fleet…
There were at least four thousand men
Killed there, not counting those who jumped
Into the sea and were drowned
And whose number nobody could say.

Sometimes John the author depended on the oral testimony of those who had “been there” – John of Earley whom we have seen above or the “people” cited elsewhere. But John the author refers to his “figures” when counting up the (enemy) French garrison at Lincoln:  611 French knights and “at least” 1000 footmen, not to mention Englishmen who were on their side. The Marshal’s army at Lincoln (1217) produced a number of counts which may have produced some precise figures: 405 knights, 317 crossbowmen.

Battle of Lincoln in 1217, depicted by Matthew Paris

John also, in describing a dramatic deed of arms at sea (part of the Battle of Sandwich), refers to a group of 32 French knights who were captured and in danger of being killed by their enemies. We can’t know who counted them, but this information seems to have come to John in the form of a list. And who wrote lists?  Clerks, who knew how to wield a pen.

John tells us about the making of one record. John says he believes the amazing record of William in his early tournament career:

I do not wish to accept anything without substance
Only what the clerks at court wrote down,
Those clerks who gave their attention to the matter
Wigant, the clerk of the kitchens
A and others too, it is the very truth,
Gave proof in writing without any guessing.

‘Ranking men’ could end up on such lists because they were worth money. This list or lists were likely produced during the “fair distribution of booty” by the Marshal after the sea battle. The booty largely consisted of ransomable warriors. The need for a list or lists of these assets was necessary for a number of reasons, including the Marshal’s reservation of some of the booty to found a hospital for the benefit of the poor. This must have been a tricky and laborious operation, and the results could hardly have been credible (‘fair’) without a defined process carried out at least in part by literate clerics.

This discussion of clerks at war provides some interesting insights into the nature of medieval warfare. In particular, we should avoid the cliché that medieval warriors only fought irrationally and were obsessed with glory,  valour, piety, revenge and prowess. There were plenty such of men, of course, and these motives were an important part of medieval warfare. But it would be hard to say that we are seeing primitive warfare here. An effective army had to include various kinds of people trained to take on a variety of roles, including vital non-martial roles. Indeed, the clerks were just one such group.

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.

Click here to read more from Steve Mulhberger

A bibliographic note: There are a number of books about William Marshal, but if you have a deep interest in William you should be aware of the 3 volume History of William Marshal published by the Anglo-Norman Text Society. My quotations from the History are taken from the translation by S. Gregory in that publication.

Top Image: British Library MS Royal 2 B. VII, fol. 240v