According to DeVries, “The single most important weapon in the Middle Ages was the sword.”

A fast-moving weapon that could stab as well as slice, the sword delivered the most damage for least effort. It allowed the development of a sophisticated form of martial art, granting fame to expert swordsmen and inspiring fighting manuals such as Fiore dei Liberi’s Flos Duellatorum (1410). As military historian Mike Loades says, the sword “gives hope that skill can triumph over brute force.”

There were other reasons for the sword’s popularity. The limits of metalworking meant that swords were initially expensive, conferring status on their owners. Because the sword was a weapon suitable for wearing, that status could be displayed both on—and off the battlefield.

The other high-status weapon was the lance, used in attacks by mounted men-at-arms. The force of a galloping horseman, concentrated through the point of a lance, gave it incredible power. But it was a one-shot weapon, often shattering on impact and was no use up close. It was individually deadly but not a war-winner.

Though swords became widespread, polearm weapons were, at one point, more prevalent for ordinary infantry.

Cheap and easy to manufacture, spears equipped the increasingly large armies of medieval rulers. Used in large defensive blocks, they provided an antidote to cavalry charges, as shown by the successes of the Scots against the English at Bannockburn (1314).

While the spear was most common, other polearms were deadlier. Equipped with axes, blades, as well as points, staff weapons could be swung with incredible force. A mace was a pole fitted with a heavy head made of stone, iron, bronze or steel.

According to DeVries, skeletons from late 15th-century Switzerland show the damage from these weapons, with skulls cracked open by the force of the blow—a deadly as well as an incapacitating attack.

Spearmen protected archers, another important feature of the battlefield. Three types of bows increased the power of medieval archers, giving them more range and capacity to kill—recurve bows, crossbows and longbows.

Even with their extra power, arrows rarely penetrated metal armor, as shown by tests at Britain’s Royal Armories. But the force of their impact could still incapacitate and shatter morale, as described in military historian John Keegan’s account of the Battle of Agincourt (1415) in The Face of Battle.

The point of most weapons was to incapacitate rather than to kill. Prisoners, especially those of high status, could be ransomed for money or leveraged for political influence. But when killing was ordered, as on Henry V’s orders at Agincourt, the daggers came out.

Medieval warriors often carried daggers designed not for cutting but for punching through the gaps in armor. These were used against incapacitated enemies, as happened to Richard III at the Battle of Bosworth Field. Based on Richard’s remains, DeVries believes that his helmet was cut off with daggers, exposing him to the attacks that killed him.

Medieval warfare was mostly decided by sieges, and here a different sort of weapon mattered. Loades refers to the trebuchet as the “weapon par excellence for the siege.” By flinging rocks repeatedly at a single point, it could hammer a hole in a castle’s defenses, letting the attackers in.

Traction trebuchets were in use from the start of the Middle Ages. The arrival of the counterweight trebuchet in the 13th century increased their power, making even great castles vulnerable. In July 1304, the garrison of Stirling Castle surrendered to Edward I rather than face Warwolf, Edward's massive counterweight trebuchet.

From the 14th century, gunpowder starting changing war, as Europeans adapted this Chinese creation for a new use—guns. One of their first uses was at the Battle of Crécy (1346), when the English fielded five cannons to limited effect. Over the next two centuries, they evolved into the devastating weapons that would make castles obsolete.

The parallel development of handguns was equally important. Used in small numbers in the 14th and 15th centuries, they were becoming prevalent as the Middle Ages ended. Easier to use than bows, they let rulers field large armies with limited training, increasing the scale of war. Emerging out of the Middle Ages, they were the weapons that ended the medieval way of fighting.

Some more unusual weapons go largely unnoticed. The caustic powder quick lime was dropped on attackers in sieges and naval battles, getting through armor and clothing to burn eyes and skin.

The humble caltrop, a spiked metal device, was scattered on the ground to puncture enemy feet. The sharp objects were important enough that Philip the Good of Burgundy included caltrops in his niece’s dowry.

Unlike many medieval weapons, it is still used today, scattered across roads by drug gangs to puncture police tires.