About this Article
Written by: Christopher Carrillo
Written on: September 5th, 2005
Tags: mechanical engineering, security & defense, history & society
Thumbnail by: Tbc/Wikimedia Commons
About the Author
Christopher Carrillo was born in Monterey Park, CA. In the fall of 2005, he was pursuing a B.S. in Electrical Engineering from the University of Southern California.
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Volume IX Issue II > The Trebuchet
The medieval battlefield was dominated by large artillery weapons, and among these the trebuchet was king. This massive weapon was eventually capable of throwing massive boulders over 250 meters, but it did not start that way. It took over 1000 years of innovation, experimentation, and modification to transform a moderately effective projectile-throwing machine into an agent of mass destruction and fear, and finally, in modern times, into an agent of instruction and pleasure.


Artillery has been the centerpiece of many armies over the centuries because of the massive amounts of destruction, fear, and uncertainty it has caused in enemy camps. This aspect of warfare has made tremendous advancements throughout history, with current artillery weapons having the capability of sending projectiles past the horizon and landing within a few feet of their intended targets. These super weapons are the result of over two millennia of trial and error that began with the development of the trebuchet.


Two of the major predecessors of the trebuchet were the ballista (Fig. 1) and the catapult [1]. The ballista "was a type of large crossbow" that worked very much like a bow, using the tension created by pulling back a string or rope along with a trigger mechanism to fire spear-like ammunition [2]. The ballista worked well against troops and cavalry, but had no effect upon walls and structures [2]. The ballista eventually gave way to the catapult [3].
Foresman/WikiMedia Commons
Figure 1: Ballista.
The catapult consisted of a solid base with a pivoting arm that would be pulled down and locked into place [1]. Once the arm was in place, the projectile would be loaded into a cup at the end of the arm. The force that the catapult needed to launch the projectile came from the manipulation of twisted ropes [3]. The catapult operator would twist ropes that surrounded the pivoting arm, causing immense tension. When the catapult was released, the ropes would twist back into shape and swing the pivoting arm upward until it reached a vertical position and hit a cushioned pad. The pivoting arm would then stop and the projectile would be flung forward. In order to change the trajectory of the projectile, the operators had the option of either "angling the whole machine or changing the angle of the crossbar" [1]. A powerful catapult had the capability to launch a 27-kilogram stone, but had little effect on walls or fortified buildings located over 160 meters away [3].