The "night dog" referred to is, of course, the Bullmastiff, the only British breed ever specifically produced for guard duties and from the two oldest, purest and bravest breeds. Technically created in modern times, it existed for centuries in the form of the lighter Mastiff when used as a hunting dog, and the bigger, faster Bulldog when used for bull-baiting. It can be argued that the Bullmastiff is a truer descendant of the original Bulldog than the modern breed of that very name.