Off topic, but if that quote rings a bell, it might be because Oliver Stone blatantly plagiarized Genghis Khan in the movie Conan the Barbarian. Two, is an extension of one, the Mongols were seriously brutal conquerors. I mean, not uniquely brutal, but still. The Mongols often destroyed entire cities, and most historians estimate the number they killed to be in the millions. Three, their empire didn't last. Within 80 years, they'd left China and been replaced by a new dynasty, the Ming, and in Persia they blended in so completely that by the 15th century they were totally unrecognizable. I mean, they'd even taken up agriculture.