A fatal design flaw in early plate armor decided the Battle of Benevento
In 1266, King Manfred of Sicily faced Charles of Anjou with an army of elite German knights. Though their new plate armor seemed impenetrable, French attackers discovered a lethal vulnerability: the armpits. This tactical revelation turned the tide, annihilated the Hohenstaufen dynasty, and reshaped the map of medieval Italy.
The Battle of Benevento, fought on 26 February 1266, was the climax of a long-standing power struggle between the Papacy and the Hohenstaufen dynasty. Manfred, the illegitimate son of Frederick II, had usurped the Sicilian throne in 1258. Pope Urban IV and his successor, Pope Clement IV, sought to replace him with Charles of Anjou, a French prince who secured the throne through a secret treaty and a campaign of conquest.
Manfred’s forces were a heterogeneous mix, relying heavily on German mercenary knights and Saracen archers. Charles, conversely, commanded a more homogeneous French and Provençal army. Despite Manfred’s strong defensive position behind the River Calore, his tactical errors proved fatal. His first line of German knights charged prematurely across a narrow bridge, becoming isolated from the rest of his army. Charles, observing this, committed his reserves to surround and overwhelm the German contingent.
The decisive moment hinged on a technological vulnerability. While the German knights wore early coats of plates that repelled standard sword strikes, French attackers identified that the armor left the armpits exposed when a knight raised his arm to strike. By targeting these gaps in close-quarters combat, the French forces decimated the German cavalry. The defeat was absolute; of 3,600 heavy cavalrymen, only 600 escaped. Manfred himself, refusing to flee, charged into the enemy ranks and was killed.
The battle effectively ended Hohenstaufen rule in the Italian Peninsula, allowing Charles to consolidate his control over the Kingdom of Sicily. The loss of Manfred's Saracen mercenaries, a force historically tied to the Hohenstaufen emperors, further signaled the collapse of the old order. Charles would later face the final Hohenstaufen heir, Conradin, at the Battle of Tagliacozzo in 1268, but the victory at Benevento had already cemented the rise of the Capetian House of Anjou.
Source: Battle of Benevento
