The mastiff dog breed holds more than one type. Both animals have a common foundation dog from which they sprang, but despite their similarities, they also have important physical, health-related and behavioral differences.
Both the Neapolitan and Old English mastiff breeds originated from a giant mastiff-type dog called the molosser that lived in early civilizations such as Babylonia as far back as 2200 B.C. The Phoenicians took the molosser to Britain by ship in 500 B.C., according to one theory, where they were bred and raised as guardians and fighting dogs, which became the Old English mastiff. Elsewhere in the world, the molosser found its way to Alexander the Great of Greece and Egypt. When Julius Caesar invaded Britain in 55 B.C., he was so impressed by the English mastiff he took several pairs back to Rome to use as gladiator dogs. These dogs, mixed with the native stock of fighting canines, became the Neapolitan mastiff.
Despite their common ancestry, both types of mastiff look significantly different from the other. The English mastiff is taller and heavier than the Neapolitan. It's also lighter colored, often fawn or apricot, or darkly brindled on a light background. The Neapolitan can be blue-grey, black, mahogany or a lighter tawny hue. The Neapolitan, though shorter, has a stockier build, shorter legs and heavier wrinkling and loose skin around the head. Both types have ears that flop forward and short tails.
Though both mastiff breeds share similar personality and behavioral traits when well-socialized, such as a guardian instinct and a politely aloof demeanor around accepted visitors to the home, they do seem to part ways as to the scale of their guardian tendencies. Overall, the Neapolitan appears to be more alert and aware, even when it seems relaxed, with a dominant and strong-willed personality. Both mastiffs get along well with cats and other dogs when raised with them. Neapolitan and English mastiffs can grow too excited and clumsy around small children who run around screaming, and their great sizes can be detrimental for that reason.
Mastiffs of both breeds can be prone to several diseases, though they are typically healthy dogs who can live up to 10 years. Two of the shared health problems are hip and elbow dysplasia. English mastiffs can also suffer from cancer, bloat, seizures, cystinuria and progressive retinal atrophy. Neapolitan mastiffs can have cherry eye, cardiomyopathy, demodicosis and fold dermatitis.