Old English Bulldog
The Bullenbeisser ("Bull-biter") became extinct by crossbreeding rather than by a decadence of the breed, as happened with the Old English Bulldog, for instance. The size of the "Bull-biters" varied from about 40 to 70 cm by 1850; the smaller dogs lived in what is today the Netherlands and Belgium, with the larger dogs in Germany. In the late 1870s, German breeders Roberth, Konig and Hopner used the smaller dogs to create a new breed, today called the Boxer, by crossing the smaller Bullenbeissers with Bulldogs brought from Great Britain. The original ancestry was 50/50. However, German owners started crossing their dogs with many Bulldog lineages, which produced an indistinguishable breed after World War II.