The American Kennel Club recognizes only one type of bullmastiff. Current breed standards call for heights of 24 to 27 inches and weights of 100 to 130 pounds.
This large, powerful breed was developed in England to assist gamekeepers in apprehending poachers. The bullmastiff belongs to a group of dogs known as molossers that descended from a type developed in Molossia, a region of ancient Epirus. They can be traced back as far as 1795. The foundation breeding was 60 percent mastiff and 40 percent bulldog. The breed was recognized by the English Kennel Club in 1924 and by the American Kennel Club in 1934.