The ways in which dog breeds find their way into guarding roles is perhaps as varied as the breeds themselves. Some ancient breeds, such as the Rottweiler, were originally bred for herding, but adapted into guarding roles through the need to protect livestock. Others, such as the Tibetan Mastiff, were bred and trained to guard sacred religious locations for as long as history has recorded them. More modern breeds, such as the Doberman Pinscher, have been bred exclusively as guard dogs in the past century. Amazingly, other modern breeds who were bred as herding dogs, such as the German Shepherd, have adapted into a wide variety of other roles, including that of a guard dog, in only a few decades. Other breeds commonly used as guard dogs today include the Belgian Malinois, the American Bulldog, the Pit Bull Terrier, and the Bullmastiff.