Ostfriesen and Alt-Oldenburger

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.