The Bullenbeisser (also known as the German Bulldog) was a breed of dog known for its strength and agility. The breed was closely related to the Bärenbeisser (some believe that the two breeds were the same; the names mean "bull-biter" and "bear-biter," respectively), and the Boxer. It was, in all its aspects, similar to the present Alano Español (Spanish Bulldog) and very alike to the Dogo Argentino, not only in aspect, but also in usage. There were two regional varieties, the Brabanter Bullenbeisser and the Danziger Bullenbeisser. The breed is now extinct.
The Bullenbeisser became extinct by crossbreeding rather than by a decadence of the breed, as happened with the Old Time Bulldog, for instance. The size of the Bull Biters varied from about 40 to 70 cm by 1850; the smaller lived from what today is Netherlands and Belgium, and the bigger, in Germany. In the late 1870s, German breeders Roberth, Konig, and Hopner used the dog to create a new breed, today called the Boxer. Some 30 Bullenbeissers were already crossed by the Boxer Kennel Club of Germany at 1900 in with Bulldogs brought from the British Isles. The blood composition was 50/50 at that time, however, the German owners started crossing their dogs with all kinds of Bulldogs and Boxers, which produced an undistinguishable breed after World War II. One reason why such quantity of German blood was used to create the Boxer dog was the wish to eliminate the excessive white colour of the breed, and the necessity of producing thousands of dogs for one of the most popular breeds in the world.