“The Mongols took over Asia because they were savage, brutal and merciless.”
I suspect they said the same thing about the Greeks, Romans, Moors, Turks, Normans, Incas, Aztecs, Boars, Nazis, Soviets, US Calvary(except Little Big Horn), Apache, Sioux and every other conquering army in the history of the world.
I think the Mongols had the largest empire based on total land mass controlled ever. From Venice to China and south to Malaysia.
Merciless brutality was not in short supply for the first 99.9% of man’s time on earth. Even today, we do a pretty good job of brutalizing our fellow man, it is just we do seem a bit more civilized than ancient man. Just a bit. LOL.