Warhorses needed to be at least somewhat trained before they could be ridden in battle. They had to learn to respond to cues from their rider’s legs rather than the reins, as the knights needed their hands free to wield weapons. Horses were known to kick and bite at enemies in the heat of battle, though it is not known whether they were trained to do so or if it was simply a natural response to the chaotic situation. Europeans were known to prefer stallions as warhorses, as their natural aggressive tendencies made them useful in battle and less likely to be frightened, but it is not known whether a significant number of stallions were actually used. If a mare nearby was in heat, a stallion quickly became a liability for anyone trying to control it. In addition, stallions often become very aggressive with one another, which presented a significant danger to them and their handlers. It would have been impractical to expect a bunch of stallions to line up close together in any sort of cavalry formation. However, some sources report that warhorses frequently fought each other in the middle of battle, often after their riders had been unseated or killed and no one was around to restrain them. They were most useful when it came to charging enemy lines and taking down soldiers on foot, so perhaps their tactical advantage would have outweighed the difficulty of handling them.
Jousting was another important way that warhorses learned the skills they needed for battle. Jousting tournaments were held frequently throughout the Middle Ages, and allowed a horse to get used to potentially frightening sights and sounds of lances striking armor and riders falling off around them. It also taught them to charge straight and respond to their rider’s cues, two skills that were essential to any good warhorse. It allowed them to build up their strength and endurance as well as get used to carrying the weight of a knight and his armor. The tournaments also gave knights an opportunity to test out prospective war horses and see which ones would be best suited for riding in battle.
While warhorses would have to build up their strength to some extent to perform at the necessary level, most of this was manifested as endurance and speed rather than actual physical strength needed to carry an armored rider. A common misconception surrounding knights’ armor is that it was very heavy—this often leads to the additional assumption that warhorses had to have been huge and draft-like to carry so much weight. Tournament armor was significantly heavier than field, or battle, armor, and still only weighed around 90 pounds. Field armor could weigh anywhere from 40 to 70 pounds, depending on whether the knight was part of a heavy or light cavalry, and the armor worn by the horse rarely weighed more than 70 pounds. All together this added up to around 1,100 to 1,400 pounds for (fully armored) horses being ridden in battle. As horses can easily carry around 30% of their body weight, such a load would have been reasonable for a heavier built riding horse, and a large draft breed would not have been necessary. Also worth noting is the need for horses within the 14-16 hand range so that knights could mount without assistance. While this was likely due in some part to the pride of being able to leap onto a horse’s back while fully armored, it really came down to necessity. If a knight fell off his horse during a battle he was left very vulnerable if he couldn’t get back on without help.
Bennett, Matthew. “The medieval warhorse reconsidered.” In Medieval Knighthood, 5. Papers from the Sixth Strawberry Hill Conference 1994, pp. 19-40. 1994.
Raber, Karen, and Treva Tucker, eds. The culture of the horse: Status, discipline, and identity in the early modern world. Springer, 2016.
“Horses in the Middle Ages.” Wikipedia. November 21, 2018. Accessed November 30, 2018. https://en.wikipedia.org/wiki/Horses_in_the_Middle_Ages.
Bennett, Matthew. The Medieval Warhorse: Origin, Development, and Redevelopment. Wiley Blackwell.
Codex Manesse, UB Heidelberg, Cod. Pal. germ. 848, fol. 52r: Walther von Klingen