The English Mastiff is a breed of large dog. National kennel clubs, including the United Kingdom's Kennel Club and the American Kennel Club, refer to the breed as simply the Mastiff. The Mastiff is a particularly large dog demanding correct diet and exercise. Excessive running is not recommended for the first two years of the dog's life, in order not to damage the growth plates in the joints of this heavy and fast-growing dog, which in some weeks may gain over 5 lb. There is a similar figurine from the same region during the Kassite period almost a thousand years earlier. There is a similar figurine from the same region during the Kassite period almost a thousand years earlier. These dogs may be related to the dogs that fought lions, tigers, bears, and gladiators in Roman arenas. The linguistic origin of the name 'Mastiff' is unclear.