This is an ancient breed, descended from very early large Tibetan dogs from which most, if not all, of today's Mastiff-type and Molossuses are descended. Some of the modern breeds thought to have Tibetan Mastiff ancestry include the Leonberger, the Newfoundland, the Kuvasz, and even the toy dog breed, the Pug, which itself was a well-established breed before the 1500s. Marco Polo encountered the large Tibetan dogs in his travels and described them as "tall as a donkey with a voice as powerful as that of a lion." They were used as guard dogs outside the sacred city of Lhasa. The breed originated in Tibet as a herding dog and guard dog and it still makes an excellent sheepdog, but, by the early 19th century, this dog had become nearly extinct in its homeland. English breeders took an interest in it and developed the Tibetan Mastiff in their own country during the first half of the 19th century. King George IV owned a pair, and there were enough of the breed in England in 1906 to be shown at the 1906 Crystal Palace show. Subsequently, however, the breed lost favor and nearly died out in England, as well.