Pit bulls were originally bred in Great Britain for a blood sport known as baiting, which involved dogs attacking bulls, bears and other large mammals. When baiting became illegal, breeders refocused the baiting breed lines for dog fighting.
The new breeding lines used the English bulldog and various kinds of terriers to create a more agile variety of dog that still had strength and a fighting spirit. These dogs were aggressive toward other animals, but they were not considered dangerous to humans. In the United States, they were often used as farm, hunting and companion dogs. Although it is a myth that pit bulls were called nanny dogs in Victorian times, they were considered loyal and gentle animals. They continued to be bred for dog fighting, but their temperament was not considered especially dangerous until the mid-1980s.