Building the Medieval Trebuchet

Saturday, January 5, 2019
Stevens C Prefunction (Hilton Chicago)
Daniel Bertrand, Utah State University
The counterweight trebuchet was the heavy artillery of the Middle Ages, using gravity to hurl projectiles and destroy fortifications. The trebuchet, a type of catapult, traveled from Ancient China to the Middle East, where it evolved to use a counterweight instead of manpower in the 12th century, allowing it to become more powerful. In the early 13th century it spread throughout Eurasia, and in the late 13th century trebuchets became monster machines, likely more than 60 feet tall, throwing stones weighing 300lbs farther than 300 yards. Trebuchets changed the political and architectural landscape of Europe until being replaced by later gunpowder cannons.

To this day, it is unclear how trebuchets were conceived or constructed. How would a master engineer design an “engine,” and how would something so large have been assembled? Learning how these machines were made can tell us why sieges succeeded or failed. Since sources with technical details are scarce, one of the best ways to answer these questions is through reproducing a machine based on extant drawings, like those of Villard de Honnecourt and Conrad Kyeser, and known techniques, like the timber joinery used in surviving buildings. While replica historical machines have been made in modern times, the majority of these are in Europe, and the tools and methodologies of making trebuchets have not been widely published.

My research traced the specifics of building and operating trebuchets with medieval techniques via construction of a half-scale machine (33 feet tall). In the emerging field of experimental history, I have documented the methodologies I used to construct my trebuchet through pictures, videos, and an online blog.

This poster argues that medieval trebuchets were constructed with timber framed wood joints, which were both sturdy and easy to disassemble. It also argues that components of trebuchets were raised into the air with lifting shears, a type of crane. My project shows that craftsmen of the Middle Ages knew how to use simple machines to accomplish complex tasks, and that assembling and operating a trebuchet is difficult. These insights give weight to the logistical difficulties of transporting and reassembling these machines at sieges, which was done later in their use. My project also shows the strength of wooden axles, used on most machines. While most of these things have been discussed independently by scholars, my project will bring all of these concepts together in the context of building trebuchets.

My poster will illustrate these arguments by featuring photos of the replica machine in various stages of its construction. These will be contrasted with drawings and manuscripts from the Middle Ages, allowing me to discuss the differences between the medieval sources, and why I chose to build my machine the way I did.

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