Let’s take a look outside of the Holy Roman Empire for a moment. At the end of the ad 1200s the ferocious and wily Mongol warrior Genghis Khan conquered everything and everywhere from the Pacific Ocean to eastern Europe. He was able to coordinate his cavalry to make lightning-quick attacks on much larger armies—seeming to strike everywhere at once—and beat them. Genghis Khan formed alliances with tribal leaders across all of Asia. The Mongolian Empire was huge, gang.
I can’t tell exactly who invented the stirrup, or when, but without stirrups there’d be no Mongolian cavalry to conquer Asia nor knights to support the feudal system in Europe. http://en.chinaculture.org/created/2005-07/21/content_70825.htm
Back to the beginning of The Western Civ User’s Guide to Reading & Writing.