The heavy warmbloods (German: Schwere Warmblüter) are a group of horse breeds primarily from continental Europe. The title includes the Ostfriesen ("East Friesian") and Alt-Oldenburger ("Old-Oldenburger"), Groningen, and similar horses from Silesia, Saxony-Thuringia, and Bavaria. Breeds like the Hungarian Nonius, Kladruber, and Cleveland Bay are also often classed as "heavy warmbloods." They are the ancestors of the modern warmbloods, and are typically bred by preservation groups to fit the pre-World War model of the all-purpose utility horse. Unlike the registries of the sport horses that followed them, many heavy warmblood registries maintain closed or partly closed studbooks. However, external evaluation and performance testing of the breeding stock is still a key element in these registries. Many of the heavy warmbloods are selected primarily for family-friendly temperaments.
European horses in the Middle Ages could fall into several categories, though as a group they were likely common, small, and primitive by modern standards. There were small, hardy farm horses, smooth-stepping saddle horses, quicker "coursers", and a very few highly prized, powerful destriers. As the availability of firearms grew, heavily armored knights and their heavy mounts became impractical "relics of the past."
The Spanish horses, ancestors of the Andalusian, the Danish Fredriksborg, and the Neapolitan horse were particularly popular among the German nobility during the 17th and 18th centuries. As they collected these stallions, the residents bred them to their native mares, setting a foundation we would identify today as "baroque". From this base of thick, primarily dark-colored horses, the Groningen, Friesian, East Friesian, and Oldenburg would eventually be born.