The introduction of the stirrup (brought to Europe from China and India around the 10th century A.D.) made it possible for a man on horseback to strike an opponent with remarkable force without danger of being unseated. Furthermore, horse breeding had developed increasingly larger and more powerful mounts who could carry sufficient weight of armor to make both horse and man virtually invulnerable.

A devastating blow could be delivered by a spear, or lance, which could be "couched" or semi-attached to the knight. Charging at full speed, the spear point would strike an opponent with the combined momentum and weight of horse, man, and armor approaching at full gallop. A formation of such knights, striking together, was an extraordinarily frightening and almost overwhelming force, combining high degrees of posturing, force, and mobility, which could only be stopped by a hedge of spears and the horse's complete and consistent unwillingness to impale itself.