While the medieval warhorse is often thought of in terms of the modern Friesian or Andalusian, the truth is very different. The horses of the medieval period would at best be passingly recognizable as contributors to the breeds we are familiar with today.
On the whole, the decline of the Roman Empire led to the general decline of the breeding stock developed during the classical period. Uncontrolled breeding resulted in a horse that was not selected for a specific purpose, and so the classical types were lost, though the gene pool was still present.
In some areas, this decline was slowed. For example, the Merovingian kingdom, which would later split into France, Belgium, Luxembourg, Germany and Switzerland, and parts of the Czech Republic, continued to maintain a Roman horse breeding center. The Spanish, famed as a horse-breeding culture, and influenced by the Moors who had brought their horses, and knowledge of horse breeding with them from the Middle East in their expansion through Northern Africa, continued to develop their own horse stock.
Following the victory of Charles Martel over the Umayyad invaders at the Battle of Tours in 732, the Merovingians were able to introduce Arabian, Barb, and Spanish stock to their own horse breeding.
The church, being literate, became heavily involved in horse breeding, in no small part because of their ability to read and write, and so record the pedigrees of the horses they bred. The Carthusian monks were behind the jennet, a forerunner to the modern Iberian and Friesian horses. In Britain, the Cistercians were heavily involved in the development of the native moorland ponies.
In the medieval period, the concept of horse breeds as many understand it today did not exist. Instead, horses were viewed in terms of types, related to their purpose or physical attributes.
Of the many types of horse found in medieval Europe, many found use as warhorses. Of these, the destrier, courser and rouncey made up a group known as chargers.
The destrier is perhaps the best known. Described in the fourteenth century as "tall and majestic and with great strength", the destrier is also known as the "great horse" because of its size and reputation. Modern analysis of horse armor in museums reveals the destrier to be around the size of a modern field hunter: 14-16hh. Though highly prized by knights and men-at-arms, the destrier was exceptionally expensive to obtain, and to keep. Many knights who owned destriers could only do so through gaining the sponsorship of a higher-ranking noble. Generally, the destrier was used for the joust.
The courser, a lighter, faster horse, was preferred by the fighting man, particularly in the pitched battles of the Crusades. Though lighter, the courser was still a strong horse. This type was frequently used for hunting.
The rouncey was a horse for more general usage, and was generally kept as a riding horse for a wealthy knight's retinue. The rouncey saw common use by squires, men-at-arms, and poorer knights as a war mount.
The jennet as a horse with a quiet and dependable nature, was popularly used as a riding horse by ladies. These small horses, bred from Barb and Arabian stock brought to Spain by the Moors also saw use as a cavalry horse by the Spanish. The Jennet contributed to the modern PRE horses, and to many of the horses taken to the Americas.
The hobby was a light horse, popular for skirmishing, developed in Ireland from Spanish and Libyan stock. Typically, they stood between 13 and 14 hands, and their great speed may have influenced the development of Thoroughbred, Standardbred and Hackney horses in the 18th Century.
In some areas, this tradition of breeding for type, rather than blood, continues today with the open studbook warmblood varieties found throughout Europe.
1. Wikipedia - Horses in the Middle Ages - Breeding
2. Wikipedia - Horses in the Middle Ages - Types of Horses
3. Wikipedia - Destrier
4. Wikipedia - Destrier - Breeding and size of the destrier
5. Wikipedia - Destrier - Value of quality war horses
6. Wikipedia - Courser
7. Wikipedia - Rouncey
8. Wikipedia - Jennet - Modern descendants and recreated breeds
9. Wikipedia - Irish Hobby
10. Wikipedia - Warmblood