The Jack Russell Terrier is a small terrier that has its origins in fox hunting in England. By the 1850s, these dogs were recognised as a distinct breed. An important attribute in this dog was a tempered aggressiveness that would provide the necessary drive to pursue and bolt the fox, without resulting in physical harm to the quarry and effectively ending the chase, which was considered unsporting. Following Russell's death, the only people who made serious efforts to continue those strains were two men, one in Chislehurst with the surname of East, and another in Cornwall named Archer. East, at one point, had several couples, all of which were descended from one of Russell's dogs.