In the history of humankind, wars have always played a crucial role. For better or for worse, some of the greatest inventions appeared precisely because of the need arisen through warfare.

In this article we will aim (if you allow the pun) at describing some of these inventions, namely the siege weapons.

Siege weapons were invented as a tool to break the otherwise often impenetrable city walls. Indeed, before the advent of catapults, trebuchets, attack towers, and other such weapons, to attack a walled city was a folly.

No less an authority on matters of warfare, Sun Tzu himself had strongly advised against it in his magnum opus Art of War. As he explained, attacking cities must be the last resort, when all other alternatives have failed.

He adds that, as a siege is usually a protracted affair, an impatient general would often mindlessly send his troops to swarm up the walls, with the result that many of them would be killed without success.

The First Rams and Attacking Towers

The crafty engineers of the time began devising siege weapons that would increase the chances of the attacking armies to take a walled city.

Possibly the first recorded use of a siege weapon in China was a "stone throwing machine" called Hui, that was used in a war fought in 707 BCE, by the King of Zhou against the Duke of Zheng.

During the same period, the Chong Che (the siege or attacking tower) was also introduced. This was, as its name implies, a mobile construction tall enough to reach over city walls.

Soldiers were hidden inside, protected (in theory at least) from enemy fire by materials such as animal skins, which formed a protective layer around the tower.

Some time later, we find the earliest mention of a battering ram – called Zhuang Che – which can be found in the Book of Odes, generally attributed to Confucius.

However, it was the Warring States period (475-221 BCE), when generals began to depend increasingly more on siege weapons, both offensive and defensive.

From Counter-balanced Buckets to Catapults

In Mohist texts of the time, we find the earliest mention of catapults based on the lever principle, as well as detailed analyses of the projectiles used – among them burning charcoal and noxious gas containers, both used to disperse enemy troops.

There are not many details regarding the design of these first catapults, but the lever principle was widely known and used, for instance, in the counter-balanced bucket, used to hoist water from wells.

In fact, a story survives that is perhaps a metaphor for the invention of the catapult. According to it, Confucius's disciple Zi Gong once saw an old man who refused to use the counter-balanced bucket to water his fields.

When Zi Gong asked the old man why he did that, the old man replied that it was a cunning device, and people who use cunning devices have cunning in their heart.

Slings and Arrows

It was also during the Warring States period that the first types of arcuballistas and crossbows found their way into siege warfare. Many of those weapons were simply larger varieties of the hand-held weapons designed for use by foot soldiers.

Although these kinds of arrow-firing devices were mostly used against enemy troop formations, they were powerful enough to penetrate fortifications as well.

One type of crossbow, the Lian Nu, was able to fire multiple bolts simultaneously, and although its accuracy was questionable, its catastrophic consequences were not.

A later report from the Tang Dynasty indicates that the Lian Nu had a range of about 500 meters, within which anything hit by the arrows would collapse, including ramparts and city towers. Even if this report were somewhat exaggerated, the Lian Nu was undoubtedly a very deadly weapon.