A castle is only as good as the soldiers defending it. And a soldier is only as good as his weapon. The evolution of these weapons drove the evolution of the castle itself. As weapons got deadlier, walls got thicker. Every arrow loop, every crenellation, and every spiral staircase in a castle was designed with a specific weapon in mind.
The Longbow: The Machine Gun of the Middle Ages
The English Longbow is legendary for a reason. Often made of Yew wood (imported from Spain or Italy for the best quality) and standing over 6 feet tall, it was a terrifying weapon of mass destruction.
- Power: It had a “draw weight” of 100-180 lbs. Imagine lifting a heavy adult human with just three fingers. When a war arrow (bodkin) was loosed, it traveled at immense speed. At close range, it could punch through chainmail and penetrate the thinner parts of plate armor.
- Speed: A skilled archer could loose 10-12 arrows per minute. A castle garrison of 50 archers could rain down 500-600 arrows in sixty seconds. This “arrow storm” darkened the sky and decimated charging cavalry.
- The Cost: The Longbow wasn’t just a weapon; it was a lifestyle. It took a lifetime to master. Skeletons of medieval archers found on the ship Mary Rose show they had deformed spines and massive left arms (bone spurs) from the immense strain of drawing the bow daily from childhood.
- Legislation: King Edward III famously banned football (soccer) in 1363 so that men would spend their Sundays practicing archery instead.
The Crossbow: The Armor Piercer
If the Longbow was a machine gun, the Crossbow (or Arbalest) was a sniper rifle.
- Power: It used a mechanical winch or lever (goat’s foot) to draw the string. This allowed for immense tension, much higher than a human arm could pull (up to 300-400 lbs). It fired a short, thick bolt called a “quarrel” that could punch through almost anything.
- Ease of Use: This was the weapon that terrified the nobility. It took years to train a longbowman, but you could train a peasant to use a crossbow in a week. Suddenly, a low-born farmer could kill a noble knight in expensive armor from 200 yards away. The Pope even tried to ban the use of crossbows against Christians in 1139, calling it “hateful to God and unfit for Christians.”
- The Downside: It was slow. You might only get 2 shots off per minute. This dictated castle architecture. Crenellations (the gap-tooth pattern on walls) exist so the crossbowman could step into the open (crenel) to fire, then duck behind the stone (merlon) to reload safely.
The Sword: Status Symbol and Sidearm
Movies show everyone using swords. In reality, on the battlefield, the sword was a sidearm (like a pistol today). Reach was king. If you walked into a battle with just a sword against a guy with a spear, you died. However, the sword was the symbol of the Knight.
- The Arming Sword: The classic one-handed cruciform sword. Designed for slashing and cutting against unarmored or lightly armored foes.
- Damascus Steel: The holy grail of metallurgy. Crusaders returned from the Middle East with blades that were sharper and stronger than European steel, possessing a watery pattern on the blade. The secret of making true Damascus steel (Wootz steel) was lost for centuries and is still debated by metallurgists.
- The Longsword: As plate armor became common, the shield was abandoned (the armor was the shield). This freed up both hands. The Longsword was a two-handed weapon used to fight armor. Since you couldn’t cut through steel plate, you used the sword as a lever to wrestle opponents to the ground (Half-Swording) or thrust the point into the gaps (armpits, visor, groin).
The Mace and War Hammer: The Can Openers
By the 15th century, a knight in full Milanese plate armor was essentially a walking tank. Swords glances off him. Arrows bounced off his breastplate. You needed to transmit shock. You needed percussive force.
- The Mace: A heavy iron weight on a stick, often flanged. Simple. Brutal. You didn’t need to penetrate the armor. A hard strike to a helmeted head would cause a massive concussion, burst eardrums, or cave in the skull without ever cutting the metal. The shockwave did the damage.
- The War Hammer: Designed with a flat head for crushing and a sharp spike (the beak) on the back. The spike was used to puncture helmets or armor joints like a tin opener.
Polearms: The Great Equalizer
For the infantry, the Polearm was the ultimate weapon.
- The Halberd: A Swiss invention. It was an axe, a spear, and a hook on a 6-foot pole. You could stab charging horses, chop through helmets, or use the hook to drag a knight off his horse. Once a knight was on the ground in the mud, he was vulnerable.
- The Pike: A 10-18 foot long spear. Used in massive formations (Phalanxes or Schiltrons). A wall of pikes made a blockage that cavalry simply could not charge. The Scots used this effectively against the English at Bannockburn.
Siege Engines: The Heavy Artillery
Before cannons, there was the Trebuchet.
- The Physics: Unlike a catapult (which uses tension/twisted rope), a trebuchet uses a counterweight. A massive box of rocks drops, flipping a long arm.
- The Payload: It could hurl 200lb stones hundreds of yards. It could also hurl dead horses (biological warfare/disease), burning tar, or even the heads of executed prisoners to demoralize the garrison.
- Warwolf: King Edward I built the largest trebuchet in history, “Warwolf,” to siege Stirling Castle in 1304. It was so terrifying that the Scots tried to surrender just at the sight of it. Edward refused the surrender because he wanted to test his new toy first. He fired it, destroyed a whole curtain wall, and then accepted the surrender.
Armor Myths: The Turtle on its Back
Myth: Plate armor was so heavy that if a knight fell over, he couldn’t get up. Reality: A full suit of field armor weighed about 20-25kg (45-55lbs)—which is actually less than the kit carried by a modern soldier (which can be 40kg+). The weight was perfectly distributed across the body. A fit knight could run, jump, climb a ladder, and yes, do a somersault in full armor. The idea that they needed cranes to be lifted onto horses is a later myth (mostly from tournament armor, which was heavier).
Conclusion
The arms race between offense (weapons) and defense (armor/castles) defined the Middle Ages. Every technological leap in steel or string forced an architectural leap in stone. When you look at a castle today, you are looking at a building designed to survive the specific weapons of its time.