This ancient breed of dog (records show their presence in 1121 BC) proudly stands as one of the strongest dogs today. Marco Polo described them as "tall as a donkey with a voice as powerful as that of a lion. "Known in Tibetan as 'Do khyi' meaning 'home guard' which indicates it's use as a protector of homes and livestock. It is classified as a primitive breed and still exhibits characteristics and adaptations necessary for it to survive in the high altitude and severe cols in Tibet. Intelligent and ferocious, they can ably fight mountain lions in the high mountains of Tibet, aided by their relatively large size. The first Western traveler to have encountered Tibetan mastiffs was Marco Polo. They were used to guard Lhasa. In 19th century England, King George owned a pair.