What is a Molosser :
Molosser is a category of solidly built, large dog breeds that all descend from the same common ancestor. The name derives from Molossia, an area of ancient Epirus, where the large shepherd dog was known as a Molossus.
Molossers typically have heavy bones, pendant ears, a relatively short and well-muscled neck, and a short muzzle.
Breeds such as the Bullmastiff, Dogue de Bordeaux, Fila Brasileiro, Pyrenean Mastiff (Mastín del Pirineo), Spanish Mastiff, Neapolitan Mastiff, Tibetan Mastiff, Cane Corso, and many others fall into the larger category of “Molossers”, are of Mastiff-type, but are not Mastiffs. The term “Mastiff” (when used alone) refers specifically to the “English Mastiff” breed. Each is a separate and distinct breed.
The Boxer breed is also included, as it is a creation from other Molossers including the Old English Bulldog.