Both Cavalry sub-types attack enemy ranged Troops. A great way to attack is to use cavalry and Swordsman only. This way the high dps Crossbowman will die before they can kill your Swordsman. Swordsman deal small damage themselves, so its not a threat. Same goes with ranged Cavalry. Short-ranged Cavalry have a chance to dodge attacks, making them a second meatshield after Swordsman.