Cavalry units are able to run down Infantry, trampling soldiers without needing to engage them. For maximum effect, have your horsemen charge an enemy unit by giving them a destination behind the target. When your cavalry meets the enemy, they will not stop to fight. Instead, they will try to break through the enemy lines, trampling as many soldiers as they can. Their success depends on the type of enemy units, and the momentum of the cavalry.
All cavalry units have their current momentum displayed on their unit icon as a vertical bar.