The Giant Schnauzer is a working breed of dog developed in the 17th century in Germany. It is the largest of the three breeds of Schnauzer (the other two breeds being the Standard Schnauzer and the Miniature Schnauzer). Numerous breeds were used in its development, including the black Great Dane, the Bouvier des Flandres, and the German Pinscher. Originally bred to assist on farms by driving livestock to market and guarding the farmer's property, the breed eventually moved into the city, where it worked guarding breweries, butchers' shops, stockyards and factories. It was unknown outside of Bavaria until it became popular as a military dog during World War I and World War II.