Tubes of Thunder: The Medieval Cannon

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For Fantasy Friday this week, I thought we’d return to medieval warfare and to something I don’t come across all too often in the fantasy stories I read: the cannon. This article covers the development of European cannons, how they were made, the gunpowder used, and how they fared in battle. Hopefully, it’ll give you a few ideas for your own tales!


When did cannons shoot onto the scene?

There’s an account of the first cannon being used in 1260 by the Mamluks in their war with the Mongols.[i] In Europe however, the first reliable reference to cannons comes from Florence in 1326, where brass cannons and iron balls were ordered to aid the defence of the city.[ii] By the 1340s they seem to be more common. The official accounts of the city of Lille record a payment for “three tubes of thunder and one hundred arrows.”[iii]

As we’ll see, these early cannons were far from perfect and mostly ineffective, but they struck fear into the hearts of men and changed the nature of warfare forever.


How did they make cannons?

The earliest depiction of a European cannon can be found in a treatise on kingship, ‘De nobilitatibus sapientii et prudentiis regum’—catchy title—written in 1326 by English scholar, Walter de Milemete.

Milemete cannon.jpg

Drawing wasn’t de Milemete’s strongest point

The cannon was made of cast iron or bronze (both were used in the early days) using similar techniques to how they made bells. These early cannons weren’t very big—historians estimate about three feet in length—with the bottleneck end wide enough to hold the shaft of an arrow.[iv]

To ignite it, a hot iron was held to a trail of powder which fed into the bowl-shaped chamber and then to the charge.

These early cannons had various names. Pot-de-fer was one such name, which in French means iron pot. In Italy, it was known as the vasi, which means vase.[v]

You may have noticed that it’s just lying on a table. Early cannons had no carts or wheeled platforms. Forget about aiming. With nothing to hold it down, the cannon would have shot up into the air upon firing, sending projectiles in indiscriminate directions. But they’d cracked the method. It just needed improving.

How did the early cannon fare in battle?

chroniques de Froissart cannon 2 small

As with any new toy, those who had cannons were keen to use them. In 1346 French historian, Francois Mezeray, noted in his account of the Battle of Crecy that King Edward “struck terror into the French Army with five or six pieces of cannon, it being the first time they had seen such thundering machines.”

They were rolled in along the flank to falter the charge of the French cavalry.[vi] The 6,000 Genoese crossbowmen, hired by the French, were rattled by the explosions and fired their bolts before they were in range of the English line.[vii] The English took advantage and unleashed incessant volleys with their longbows, butchering the French and sealing victory.

But the cannons did little if any damage. They were more of a showpiece. A “look how big my dick is,” kind of thing, and caused more problems than they were worth.

Everyone loves a scapegoat, and the blame was placed at the door of the crafting process. Casting was a demanding and costly method requiring skilled craftsmen, and there weren’t many about. So a new method was sought.[viii]


Back to the drawing board

Nearly six hundred and forty-three years ago, Jehan le Mercier, a Counselor to the King of France, was instructed to organise the manufacture of ‘un grand canon de fer.’ “A big fucking cannon.” Not really. It translates to “a big iron cannon”. The vase shape was abandoned and a more cylindrical one sought.

With casting forgotten, the barrel of the cannon was built from longitudinal strips of iron which were welded together with heat and hammer. They were then secured with iron rings which were heated and passed over the tube to keep the shape rigid. Ninety pounds of rope was then wrapped around it to give even more solidity. Lastly, hides were used as a covering to protect from damp and rain.[ix]

This new design proved far superior: more accurate, powerful, and reliable. For an example, we can look back to 1377. Philip the Bold, Duke of Burgundy, commissioned the construction of a monster cannon, one which could fire a ball weighing forty hundred and fifty pounds. It was reported to have taken nine men nine days to build and was tested at the Siege of Odruik. How did it fare? Medieval author, Jean Froissart, reveals all:

“The castle of Odruik was situated on a motte, surrounded by a ditch filled with very large spikes … The Duke of Burgundy set up his cannons and fired maybe five or six quarrels in order to provoke surrender. Three quarrels were such that, because of the power of the discharge, they penetrated the walls.”[x]

The key detail we can take from Froissart’s account is the ‘power of the discharge.’ And this leads us to gunpowder.



The ingredients of the gunpowder of the day were as follows:

41% Saltpeter

29.5% Sulfur

29.5% Charcoal

These ingredients were ground down into a fine powder and mixed together. This mix was tossed into the cannon with little to keep it together. It invariably led to irregular ignitions and fires continuing after the explosion. Much gunpowder was wasted which those with coin didn’t like. Saltpeter was scarce meaning the price was high—twice that of iron.[xi]

There was another problem too. When transported the mixed powders unmixed themselves.  Being heavier, saltpeter and sulfur shuffled to the bottom of the barrel, leaving charcoal sitting on the top. This meant it had to be mixed at the cannon, causing delays, and presented the risk of friction ignitions. Careless hands could see them blown off.[xii]

In the early fifteenth century, some clever bastard came up with a solution: ‘corning’. The mixing process was altered so instead the powders were wetted to make a paste. This was then spread out into a thin cake and left to dry. It was a game-changer. The ingredients held together, it was easier to transport, easier to load into a cannon, and above all, led to more consistent, faster, and violent explosions.[xiii]


Another problem?

Nothing’s ever straightforward, is it? The much-improved gunpowder proved too powerful for the cannons. The explosions within practically blew them into the pieces that assembled it.

But a solution was at hand: revert to the past. By the middle of the fifteenth century, casting was being used again to make cannons. The solid form gave more stability and strength to house the violent explosions within.[xiv]

But still, the cannon wasn’t perfect. The last problem was its mobility.


The mobile cannon

Before someone thought to stick it on wheels, cannons were laid out on tables or platforms or even just the floor.

One of the first wheeled artillery machines cropped up around the end of the fourteenth century. It was known as ‘the organ gun’.




As you can see from this contemporary version, it holds similarities to the church organ, which is why it got its name. These smaller barrels could cover a broader stretch of the battlefield, spraying infantry or cavalry and faltering lines. It wasn’t as effective as it sounds, but one thing it did have was wheels. It was placed upon a two-wheeled cart and could quickly move positions on the battlefield.[xv]


Within the space of about 200 years, the Europeans hook great strides toward mastering the art of the cannon. They discovered the three basic requirements: cast forged guns, a reliable and powerful propellant, and mobility, a formula which continued to be used for centuries after.


The Compleat Cannoniere, John Roberts, 1652



You’ll no doubt notice the footnotes throughout the text. I’ve decided to do this from now on. It’s something I ought to have done from the start. In telling you what my sources are—and I strive to use only the most reliable—you can read in the knowledge that it’s not a load of nonsense, but a credible and helpful source.

[i] (

[ii]Pg. 201, H.W. Koch, ‘Medieval Warfare’

[iii]Pg. 202, H.W. Koch, ‘Medieval Warfare’

[iv]Pg. 203, H.W. Koch, ‘Medieval Warfare’

[v] Pg. 204 H.W. Koch, ‘Medieval Warfare’



[viii]Pg. 205, H.W. Koch, ‘Medieval Warfare’

[ix]Pg. 206, H.W. Koch, ‘Medieval Warfare’

[x] Pg. 59, ‘The Artillery of the Dukes of Burgundy 1363 – 1477’ R.D. Smith and K. De Vries.

[xi]Pg. 206, H.W. Koch, ‘Medieval Warfare’

[xii]Pg. 206, H.W. Koch, ‘Medieval Warfare’

[xiii]Pg. 207, H.W. Koch, ‘Medieval Warfare’

[xiv]Pg. 208, H.W. Koch, ‘Medieval Warfare’



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