The ancient Tibetan Mastiff, a descendant of the Mollossus mastiff, may have been in existence as early as the stone or bronze age. Mollossian dogs accompanied Alexander the Great from Tibet to Europe, and during this period helped found many of today's other mastiff breeds. Tibet later closed its doors to Westerners, so the breed developed for centuries in relative isolation. In the mid-1800's, a Tibetan Mastiff was given to Queen Victoria of England. Soon more dogs were imported to England and the British began to refine and standardize the breed. In the 1970's foundation stock was imported from India, Ladakh, Afghanistan and Nepal to the United States. The Tibetan Mastiff is very rare in his native land, though some dogs are now being exported from Tibet. The breed is gaining popularity in England and the United States. The Tibetan Mastiff is an excellent livestock guardian, willing to fight fiercely against predators and intruders.