In the Middle Ages, horses were specially bred to meet the requirements of warfare and chivalry and the needs of the mounted knight.

It is commonly believed that the great war-horses, also called destriers, were developed during the Middle Ages to support the great weight of the armored knight. Actually, a good suit of armor was not over 70 pounds in weight; and therefore, the horse would only be expected to carry some 250 to 300 pounds. The real reason large horses were useful was because their weight gave greater force to the impact of the knight's lance, both in warfare and in the tournament. A destrier weighed twice as much as a conventional riding horse; and when the knight struck a conventionally mounted opponent, the impact could be devastating. The destrier was sometimes shod with sharp nail heads sticking out so that he could trample foot-soldiers in his path. The destrier was a very potent weapon, and yet his descendants are the mild mannered and docile work horses of today who put their strength to less brutal use.