The Staffordshire Bull Terrier, commonly called the Staffy or Stafford, is a shorthaired, purebred breed of dog in the medium size range. Staffords originated in the Black Country of Staffordshire, the county for which they are named. The breed is classified in the terrier group, one of several group designations used by various breed registries. It has been generally agreed by authorities that the Stafford's earliest beginnings trace back centuries to mastiff types when the old bulldogs were closely linked, and used for bull and bear baiting which required large dogs in the 100–120 kilograms (220–260 lb) range.After Parliament passed the Cruelty to Animals Act 1835, dog fighting became a clandestine sport. Breeders migrated away from the heavier bulldogs, and introduced terrier blood into their crosses for gameness and agility. These ancestral crosses of bulldogs and terriers produced the first "bull and terriers". In the grand scheme of canine history, the story behind the modern Staffordshire Bull Terrier is rather brief and somewhat confusing due to the multiple aliases that were hung on these dogs in centuries past, such as the Patched Fighting Terrier, Staffordshire Pit-dog, Brindle Bull, and Bull-and-Terrier. Similar crosses were also called half-and-halfs and half-breds but were more commonly known as the bull and terrier, which was not a bona fide breed but the ancestral progenitor of several modern breeds.