The Evolution of Artillery: From Trebuchets to Cannons, and the Fall of Castles

Long before the massive counterweight trebuchets of popular imagination, the standard siege engine that dominated ancient and medieval warfare for over 1,600 years was the 'traction trebuchet'—a machine powered by dozens of soldiers pulling ropes in unison.

First recorded in 4th-century BC China by Mohist engineers, traction trebuchets evolved through Cao Cao's famous 'Thunderball Catapults' (Pili Che) in the Three Kingdoms era into standardized artillery documented across Chinese military treatises. Transmitted along the Silk Road, they became known as the 'Manganon' in the Byzantine Empire and the 'Manjaniq' in Islamic caliphates, serving as the dominant artillery from East Asia to the early Crusades in Europe.

The secret to its millennia-long dominance lay in its remarkable mobility and rapid rate of fire. Without needing tons of counterweights or cumbersome winches, crews could simply pull on command, hurling 10 to 50 kg stones, incendiary pots, and early explosive missiles at a blistering pace of 2 to 4 rounds per minute directly onto enemy formations and ramparts.

However, traction trebuchets faced an inescapable physical limitation. Relying solely on human muscle, they could not launch multi-hundred-kilogram boulders capable of shattering massive stone fortifications. As fortresses grew taller and thicker, this shortcoming paved the way for the next great revolution in siege warfare: the counterweight trebuchet.

👉 Related War: Three Kingdoms Wars

Early catapults relied on traction, with dozens of men pulling ropes simultaneously to fling a stone. Because they relied on human strength, the size of the projectiles was severely limited. However, around the 12th century, engineers in the Islamic world and the Mediterranean made a groundbreaking innovation: they replaced the teams of men with a massive wooden box filled with earth and stones.

This was the birth of the 'counterweight trebuchet'. By harnessing the immense physical energy of a falling heavy weight (gravity), armies could now hurl massive boulders over incredible distances. Amidst the fierce battles of the Crusades, this terrifying mechanical giant reigned supreme as the ultimate wall-smashing siege engine.

👉 Related War: The Crusades

As seen in the Chinese character for artillery (砲/礮), which originally contained the radical for 'stone' (石), ancient artillery relied on hurling massive boulders using leverage and counterweights rather than chemical explosions. Behind these stone-throwing engines lies a fascinating journey of technological exchange across Eurasia.

The traction trebuchet, originally invented in ancient China, had traveled along the Silk Road to the Middle East and the Mediterranean. There, Islamic engineers transformed it into the vastly superior 'counterweight trebuchet'. In the 13th century, under the pan-Eurasian Mongol Empire, this upgraded superweapon made a dramatic return journey back to East Asia.

At the time, the Mongols were struggling to conquer the Southern Song Dynasty because the formidable fortress city of Xiangyang held out stubbornly for over five years. Kublai Khan summoned master Muslim engineers from Persia and the Middle East to build state-of-the-art counterweight trebuchets on the front lines. The Chinese called this terrifying weapon the 'Huihui Pao' (Muslim Trebuchet), named after the Muslim engineers who built it.

The multi-hundred-kilogram boulders hurled by the Huihui Pao smashed into Xiangyang's ramparts with devastating force, quickly breaking the long stalemate. In an extraordinary twist of history, a siege engine that originated in China traveled across Eurasia, evolved into a terrifying new form in the West, and returned to deliver the decisive blow that brought about the downfall of the Southern Song Dynasty.

👉 Related War: Mongol Conquest of the Southern Song

Long before counterweight trebuchets reached the peak of mechanical siege warfare during the 13th-century Mongol conquest of the Southern Song, a completely different revolution was already taking root in 9th-century Tang Dynasty China: the invention of gunpowder.

The invention of gunpowder is deeply rooted in the unique political background of the Tang Dynasty. The Tang imperial house (the Li family), which had nomadic Xianbei ancestry, sought to solidify its legitimacy and imperial authority over the Han Chinese majority by claiming direct descent from Laozi (Li Er), the ancient founder of Taoism.

To reinforce this royal prestige and counterbalance the influence of powerful Buddhist monasteries, the Tang court poured immense state resources into patronizing Taoism. With generous imperial funding, Taoist alchemists spent decades conducting secret laboratory experiments in search of the 'Elixir of Immortality' for the emperors.

Around the 9th century, while compounding mixtures of sulfur, charcoal, and saltpeter, these alchemists accidentally triggered a violent explosive reaction. The imperial quest for eternal life had ironically produced gunpowder—the most destructive chemical substance of the premodern world. First appearing in primitive forms such as fire arrows during the late Tang period (like in the Huang Chao Rebellion), gunpowder continuously evolved through the Song Dynasty, eventually transforming warfare during the Mongol conquests and reshaping world history.

👉 Related War: Huang Chao Rebellion

Advancing beyond primitive bamboo fire lances that merely spewed sparks, metallurgists in the late 13th century began casting bronze and iron barrels capable of withstanding explosive pressure. This heralded the arrival of the 'Hand Cannon' (Handgonne).

True gunpowder artillery—using metal barrels to fire projectiles propelled by explosive powder—first appeared on a large scale in the late 13th century during the wars between the Song and Mongol (Yuan) dynasties. In 1287–1288, Kublai Khan deployed dedicated artillery units to suppress the rebellion of Prince Nayan. The excavated 'Heilongjiang Bronze Hand Cannon' (inscribed 1288) remains the oldest surviving dated metal firearm in the world.

During this foundational era, there was no technical distinction between a 'gun' and a 'cannon'. Both operated on the identical principle: packing gunpowder into the sealed base of a metal cylinder and propelling a projectile out the front.

The branch that grew massive and was mounted on the ground or siege carriages to pulverize fortifications became 'artillery' (cannons). Meanwhile, the branch miniaturized for an infantryman to tuck under an arm and aim at individual targets became the 'hand cannon'. Ignited by touching a burning slow match by hand, the hand cannon would evolve into the matchlock arquebus, the musket, and modern rifles—serving as the direct ancestor of all personal firearms.

By the late 14th and early 15th centuries during the Hundred Years' War, European warfare entered the era of the massive siege cannon: the 'Bombard'. Because casting a single flawless, giant piece of iron was technologically difficult at the time, smiths built these weapons just like wooden barrels (casks)—arranging long wrought-iron bars into a cylinder and hammering glowing iron hoops tightly around the outside. This is why gun tubes and artillery pieces are still called 'barrels' today.

Bombards hurled massive spherical stone balls weighing 50 to over 200 kg directly into castle fortifications. While their kinetic destructive power was terrifying, their multi-ton weight made them agonizingly difficult to transport, and the constant risk of catastrophic barrel bursts limited their firing rate to only a handful of shots per day. Nonetheless, they heralded the inevitable downfall of traditional high curtain walls.

As foundry techniques advanced rapidly, risky built-up iron construction gave way to massive one-piece cast-bronze cannons capable of safely handling immense explosive pressures. Most notably, in 1453, the Ottoman Empire deployed gigantic monolithic bronze super-cannons cast by Urban to smash the supposedly impenetrable Theodosian Walls of Constantinople. On the battlefield, the once-invincible armored knight found his expensive armor completely useless against the sheer kinetic force of a cannonball.

👉 Related War: Hundred Years' War / Fall of Constantinople

In the mid-15th century, the decisive factor that brought the Hundred Years' War to a close was the visionary military reform led by Jean Bureau, Grand Master of Artillery under King Charles VII of France, and his brother Gaspard.

The Bureau brothers abandoned fragile assembled iron cannons in favor of unified cast-bronze and iron barrels, mounting them on wheeled carriages to achieve unprecedented tactical mobility. They also standardized the 'Culverin'—a long-barreled cannon firing cast-iron cannonballs with superior muzzle velocity and range—establishing the world's first true field artillery system.

This revolution reached its zenith at the Battle of Castillon (1453), the final clash of the Hundred Years' War. Jean Bureau built a fortified field camp ringed by deep ditches and earthen ramparts, positioning roughly 300 cannons along the entire perimeter. This created an all-around defensive stronghold where enemy forces would face direct artillery fire regardless of which direction they approached from. When English knights and archers made a reckless frontal charge, they were torn apart by devastating cannon fire. This decisive engagement ended 116 years of conflict and marked the first battle in world history decided decisively by field artillery.

👉 Related War: Hundred Years' War - Battle of Castillon

With traditional high and relatively thin medieval walls easily crumbling under direct cannon fire, military architecture had to adapt rapidly. This led to the creation of the 'Star Fort' (Trace Italienne) in Europe.

Star forts featured low, incredibly thick earthen walls designed to absorb the impact of cannonballs rather than shatter. The evolution of artillery—from mechanical trebuchets to gunpowder cannons—not only rendered the medieval castle obsolete but laid the groundwork for the modern era of state-funded armies.

👉 Related War: Thirty Years War