Originally the breed was developed as an animal fights and wars, and as protectors of estates. Therefore, the protective nature is in built in them. Kublai Khan was said to have a battalion of 5000 Mastiffs. In many cases of history we find them dying in fights and war. This inhumanly behavior towards them caused the extinction of the breed in early 19th century.
There is a legend that Mastiffs are reincarnated souls of Monks and Nuns. Tibetans believe that souls of monks and nuns were not good ones to get birth as a human. That is why the Mastiff is ready to protect the local monasteries and villages.
Well, we don’t know the reality of such stories, but this is true that Mastiff is very interesting breed that is gradually becoming popular among dog lovers. They are ancient dogs who survived a dreadful history. If loved he can be your most loyal companion.