In February 1266, factions backed by the emperor and the pope were fighting for control of the Kingdom of Sicily and its lands in the Italian peninsula. The pope had called Count Charles of Anjou to lead an army into Italy, and the usurper Manfred, king of Sicily, had been slow to react. Charles rushed his army across the Apennines and found himself trapped between the rainy mountains and the River Calore, but Manfred crossed the river by the bridge at Benevento and attacked. Some of the hardest fighting was between Manfred's German knights and their French counterparts. Oman describes the fighting as follows:
Manfred's army was composed of very heterogeneous elements. The best part of it consisted of his German mercenary horse, twelve hundred strong: these troops, as the chroniclers note, were armed with the plate armour which was just beginning to come into fashion, and not with the usual mail-shirt and gambeson of the thirteenth century. … Assailed now by double their own force, the Germans still held out gallantly, and it appeared at first as if they were about to drive the foe back. They seemed invulnerable in their double harness to the French swords. But the enemy ere long noticed the weak points of their equipment; plate armour was still in its infancy, and the pieces were not protected by the scientific à l'estoc
