Hercules, the most famous mastiff

The English Mastiff, often called simply Mastiff, is a large breed of dog descended from the ancient Alaunt and Molosser.

This breed is powerfully built. With a massive body, broad skull and head of generally square appearance. It is one of the largest dog breeds in terms of mass, though the Irish Wolfhound and Great Dane are taller but not nearly as robust.

The Mastiff breed is a combination of dignity and courage; calm and affectionate to its master, but capable of protection. This particular mastiff-type breed is an extremely capable guard.
One of the famous English mastiff is "Hercules" (a.k.a. "the Beast"), from the film The Sandlot (played by Ch. Mtn. Oaks Gunner)