The history of the Rottweiler was not very well documented. It is common "fact" that they descended from Roman mastiffs while they were out conquering the world. But, many Rottie experts disagree. Some believe that the Rottweiler descended from the Swiss Mountain Dogs, (Bernese Mt. Dog, Greater Swiss Mt. Dog, and there are two more that I can't remember), still others believe that the Rottweiler came from the Tibetan Mastiff. Who knows????