In addition to his work to support troops with better ladders and bridges, Leonardo also designed or improved a number of different weapons. Guns, cannons, and other artillery weapons were on the rise during the Renaissance. Newer was better, especially when it came to national defense. Leonardo appeared to have had a nostalgic side, though, because he still spent time working to perfect or improve older weapons such as catapults, slingshots, and crossbows.

Did Leonardo invent the crossbow, or just refine it?

One of his innovations was the rapid-firing crossbow, but his was not the first design for such a weapon. The crossbow had been around, in one form or another, since about 400 B.C. The earliest crossbows were made of wood and designed to be mounted, then fired by a single soldier.

The Crossbow

The early crossbow design was easy to construct and could be shot by just about anyone, so it quickly became a desirable weapon. In fact, the Chinese army utilized crossbows extensively for generations. As crossbows spread to Europe, they were scaled down and re-engineered so that they could be carried by individual soldiers. They were highly effective, and were routinely used throughout the Middle Ages.

Leonardo's design was for no ordinary crossbow—it actually included four crossbows and got its power from a large treadmill. But not the kind you'd work out on at the gym. A number of men walked on steps that were located around the outside of a large wheel, and as they made the machine rotate, an archer would fire each crossbow, reloading them in sequence.

What was unique about Leonardo's design is that it represented both a technical and cultural shift in thinking. From an engineering standpoint, creating the gears and steps was a doable feat. More importantly, though, it brought soldiers together as they strove to reach their common goal: winning the battle. It also changed the fundamental nature of the crossbow from being a weapon that an individual used on his own, to something that required a collaborative team effort. Leonardo's crossbow was as much a redesign of society as it was a redesign of the weapon itself.

Larger than Life

Leonardo also designed a mammoth seventy-six foot crossbow that required six wheels to maneuver it. This device, also called a ballista, used a series of gears to draw back the bow; a simple strike of a pin would release the shaft. Leonardo believed that this giant weapon would operate in almost complete silence, but his claim was never tested because the device was too difficult to build given the abilities of the day. Similarly, he also designed a giant slingshot that required a series of springs to tighten it.

In the interest of defeating more enemies faster, Leonardo also designed a rapid-loading catapult system. This machine, which could be mounted on top of a wall, consisted of a rope and winding mechanism used to bend back the arm and, in effect, ease the firing process. Leonardo also designed a row of catapults that could all be launched at the same time when hit with hammers. Specially designed missiles with gunpowder inside had fins on the tail for extra stability. When they hit their target, strikers inside ignited the gunpowder and caused an explosion. These sound remarkably similar to modern artillery shells.

Were Leonardo's giant weapons actually usable, or were they just an example of “bigger is better” taken to an extreme? We'll never know, because they were never built.