Reconstructing Medieval Artillery - Archaeology Magazine Archive

A publication of the Archaeological Institute of America

Special Introductory Offer!
Reconstructing Medieval Artillery June 14, 2005
Updated July 26, 2005

Archaeologist Peter Vemming takes a hands-on, experimental approach to his studies of centuries-old arms.


Archaeologist and medieval weapons expert Peter Vemming (Courtesy Peter Vemming)

Work has begun on a 22-ton fourteenth-century trebuchet at Warwick castle in southern England. The largest reconstructed trebuchet ever attempted, it is the work of medieval weapons expert Peter Vemming of the Danish Medieval Centre. Once it is completed in late June, the siege weapon will launch projectiles--sending them up to 300 meters--daily throughout the summer. Vemming recently spoke to ARCHAEOLOGY about the new trebuchet and other projects he and his colleagues have worked on, including the re-creation of an early fourteenth-century Scandinavian cannon.

How did you first get interested in medieval weaponry and, especially, in reconstructing trebuchets?
Very early in my life even before going to the university--probably from reading Prince Valiant. As an archaeologist at a local museum, I suggested we reconstruct a medieval trebuchet for the 700th anniversary of the city Nykøbing Falster. At that time, in 1989, I think that only Napoleon III had tried something like that in 1851. His machine broke down after a few shots and the first trial shot was minus 70 meters because there was not enough curvature on the iron hook holding the ammunition sling! This was a bad result for Napoleon, but good information for us and we succeeded in building a reconstruction of a medieval siege engine, which still shoots nearly every day for the visitors at the Medieval Centre in Denmark.

How did your early reconstructions lead to the creation of the Medieval Centre in Denmark?
The reconstruction drew so much public attention that the idea of starting a center was born. During the next few years we made several reconstructions of medieval artillery. A few years later the center had been so successful that either we had to close the center, because there were not enough facilities for staff members and the visitors, or invest a lot of money. So the Medieval Centre in Denmark was created!

[image] The debut of an earlier trebuchet reconstruction in 1989, at the Danish Medieval Centre (Courtesy Peter Vemming)

What is the origin of the trebuchet? When did they first make their appearance on the Western Europe battlefield?
Mechanical devices for warfare are known way back in history, but it is commonly agreed that this type of artillery originated in Asia, and that the idea for trebuchets was born in China. From here the knowledge spread westward in the sixth century and reached the Arabs via Persia and Byzantium. From them it spread to Sicily, and the Europeans then started to experiment with this knew technology, which resulted in the creation of the very heavy counterweight trebuchet. This happened in the ninth century, and this new kind of heavy and reliable artillery dominated warfare into the first half of the sixteenth century, together with new and very potent gunpowder artillery.

How effective was the trebuchet?
A counterweight trebuchet is a very simple, very powerful, and very reliable technology. Once you have set it up it can work continuously with high precision for months without much maintenance.
   It was used throughout the medieval age to besiege castles and cities. Even though we don't have much information on the construction details of the weapon we have a lot of sources that tell us about its effectiveness in warfare. The counterweight trebuchet was the ultimate heavy artillery of the medieval age and though they surely used a lot of mechanical devices in warfare, many maybe very specialized ones, none had the same effects as the big trebuchets!
   We have several accounts of the use of a trebuchet as the decisive factor in the siege of a castle from Edward I in the Welsh wars in the late thirtheenth century. We know how many stone bullets were used, how much they cost, how many horses and wagons were used to bring the trebuchet to the castle, the wages of the blacksmith, and even the cost of pigs' fat for greasing the axles. It took 480 great stones to make the castle surrender and not a single attacker was killed. At the rate of a stone every 15 minutes this siege would have taken 80 hours!

In your 1992 article about trebuchet reproduction, published in Acta Archaeologica, you mention a number of earlier attempts to re-create this weapon, including the attempt by Napoleon III. Today, there are hundreds of groups around the world devoted to trebuchets, what makes these siege weapons in particular so popular?
Again, it is simple and reliable technology that everybody can build. It is fun to play with, but also a bit dangerous. But that is not the whole truth, once you start working with the technology you become fascinated with all the variables that have to be in harmony for the perfect shot--the length of the sling, the curvature of the release pin on the throwing arm, the length of the throwing arm, the weight in the ballast box, the weight of the bullet, etc. It sort of grabs you. It is probably the best hobby a "big boy" can get!

[image] Two men dressed as medieval soldiers load the trebuchet. (Courtesy Peter Vemming)

From what sources did you draw your plans for the trebuchet? Were you able to consult any archaeological evidence?
Unfortunately we don't have any archaeological evidence. The only fully preserved machine was excavated under a church in 1890s at Liebemuehl in East Prussia, but shortly after excavation it was cut up for firewood. So the sources we used for the reconstruction are written sources and illustrations, combined with an overall knowledge of medieval craftsmanship--the metalwork and different types of joints in the timberwork. The quality of these sources differs, and a reconstruction cannot be based on a single source alone, but has to be put together from many different places. What we build could be described as the sum of knowledge at this moment of time--something that might change if we learn more, for example by the excavation of a fully preserved trebuchet--though that is probably very unlikely!

In terms authenticity in construction, do you have a strict set of rules for materials and tools?
The authenticity of a reconstruction always goes hand in hand with the amount of money you have. We distinguish between replicas and copies. A replica is built with the old tools and materials reconstructing the old working processes, while the copy looks like the finished replica, but it is done with modern tools and devices, lifting gear, etc.
   Before each reconstruction we agree on a set of rules on which we build the machine and often we choose the replica way, not that it will have any affect on your test results, but because it is very interesting for the visitors to the center to see the old crafts being used. The big machines though, are built as copies.

Were there any surprises or new problems you encountered in building such a large trebuchet this time?
Not really. We work a lot with models before doing the big machine and we have so much experience from all the years, that we didn't meet any surprising problems.

What can a full-scale reproduction like this teach us about medieval warfare?
What would we know if we didn't build one? Experimental archaeology is a fantastic tool for understanding all the missing links in the working processes. We learn about the effectiveness of the machine itself, but also about the logistics, craft specialization, and handling of heavy machinery, you name it! But it all rests on the quality of the reconstruction; if you don't do your best there--if you use modern solutions or cut corners--the value of your results drops drastically!

What have your reconstructions taught you about the quality and precision of medieval engineering and workmanship?
At the Medieval Centre we have a windmill standing close by the trebuchets. This windmill needs repairs very often, but the trebuchet just keeps shooting and it only needs a little pigs' grease once in a while. The windmill is very recent technology (late eighteenth century), while the trebuchet represents thousand of years of know-how and craftsmanship--knowledge we have lost today.

What plans do you have the future in terms of medieval weaponry reconstruction?
For the last four years the Medieval Centre has hosted an international seminar on early guns and gunpowder. Scandinavia probably has the oldest medieval gun--the so-called Loshult gun. We have reconstructed this gun and together with the Danish military have tested it with gunpowder made from original recipes and with original materials. This research has shown that even though many scholars think of these guns as being very ineffective, it is quite opposite--these guns and powders are very efficient and the gunpowder is of nearly modern quality. The interesting question is now, if you had such effective guns in the 1350 then why does it take more than 200 years for these new weapons to conquer the old mechanical artillery on the battlefields around Europe?

[image] Left, mining for sulfur in Iceland to make gunpowder for the Loshult gun according to a medieval recipe. Right, Vemming tests his reconstruction of the fourteenth-century Loshult cannon at a Danish military base. (Courtesy Peter Vemming) [image]

   The answer, we believe, lies in the raw materials for powder making. The sulfur could only come from Iceland or Sardinia and the saltpeter had to come from Bengali in India, or you had to make it yourself, which wasn't very effective. The saltpeter came with the old trade routes from India, but in 1453 the Turks took Constantinople and this trade stops. It now became vital to find a seaway to India to get the saltpeter. The problem was not to using this technology, but securing the stable delivery of raw materials. It took 200 years for the Europeans to solve this logistic problem and from then on they started to conquer the world with these new gunpowder weapons.

* For more information on the Medieval Centre and Peter Vemming's reconstructions visit their website.


How did construction of the trebuchet at Warwick castle go?
The machine itself was built by English carpenters from my drawings, while we made the iron fittings here in Denmark. There are more than two tons of iron on it. All the parts were then sent to Warwick castle in England, where the two work crews met and put the thing together. The machine sits on a little island by the river Avon and it was not possible to get heavy lifting gear on the island, so the timbers had to be raised by hand using blocks and tackles and a simple A-frame as a crane, exactly as they would have done it in medieval times. It took a lot of manpower, but everything went very smoothly.

[image] The newly constructed trebuchet at Warwick Castle (Courtesy Peter Vemming)

Were the test firings a success?
When the machine's frame was up we started rigging it--putting on the ropes for pulling down the arm and then attaching the sling bag. Then, it was time for the first trials, we pulled down the arm to see if everything worked well, ran in the treadmills (the large wooden wheels that serve as a winch), and checked all details before putting in the counter-weight in the ballast box. The Warwick people wanted the projectile to land 250 meters down the island, so, judging from our experience with our Danish trebuchets, we put two-thirds of the weight of the projectile in the ballast box. The first shot was 280 meters, so we just stopped there and didn't put in more ballast.
   Subsequent test shootings showed the normal pattern: the bullets landed very close together in a series of shots. But then it started to rain and we had some very strange results. We know that the ropes pull together when they get wet, and that the range of shot changes a bit, but were surprised to see some very long shots when the ropes got wet. It was only days after that we got the explanation from a bright guy, who remembered that the ballast stones we put in for counter-weight were made of soft sandstone, which absorbs water very easily. By accident, we had added a lot of weight suddenly and therefore the longer shots.
   The throwing arm of the machine is very light--suitable for museum purposes, so to speak--and it will only shoot with a 15-kilo bullet. Had this been a real medieval machine the arm would have been made more solid and the ropes, etc., would have been heavier and stronger.

[image] Medieval Center employees gather sulfur in Iceland the old-fashioned way. (Courtesy Peter Vemming)

What's your next project?
Our next project will the be to reconstruct a very big medieval gun of the so called Anholt type or Mary Rose type [as on Henry VIII's warship of that name] and test it with gunpowder made from the original recipes. We have just finished collecting the necessary sulfur from the big deposits in Mamfjall in northern Iceland. Working together with the local Akureyri Museum, employees from the Medieval Center in Denmark reenacted the medieval process of extracting sulfur. This sulfur will be used for making gunpowder using early recipes and then tested in replicas of medieval guns together with the Danish army.

* The Danish Medieval Center's trebuchet is now on display at Warwick Castle in England where it will be shot daily throughout the summer. For more information visit Warwick Castle's siege weapon site.

© 2005 by the Archaeological Institute of America