The Alt-Oldenburger and Ostfriesen are representatives of a group of horse breeds primarily from continental Europe called heavy warmbloods. The breed has two names because the same horse was bred in two regions in the most north-western part of Germany: East Frisia and the former grand duchy of Oldenburg. The name Alt-Oldenburger - alt meaning "old" - simply distinguishes this horse from its descendant, the modern Oldenburg, which is bred for sport.
The AO/OF is bred by preservationists to fit the pre-World War model. Unlike the registries of the sport horses that followed them, their studbook is partly closed. However, external evaluation and performance testing of the breeding stock is still a key element in these registries. To understand the history of the Ostfriesen and Alt-Oldenburger, an understanding of the people who bred them is helpful. Traditionally, the region settled by the Frisians was highly agricultural, based on the fertile though marshy soil. Though Hanover is geographically close by, its terrain is more hilly and their cultures were far apart. Furthermore, the region of Oldenburg was passed back and forth between Denmark and Germany. This unique cultural mixture gives the region a distinct identity all its own. The story of the Ostfriesen and Alt-Oldenburger is that of horse breeders responding to a dynamic market.