How did the nomadic aspect of mongol society contribute to its rapid expansion?

Because Mongols were nomads; which means they didn't have any permament settlements, this enabled them to cross different terrains more quickly; they were also expert horsemen and were thought to be able to shoot an arrow from full-speed horseback at great distances.

Because they were nomads and very proficient with the bow they could plunder and pillage different villages and even cities. Through this, they could then siege and besiege them as well. This in the end culminated in the great Mongolian empire, one of the biggest empires in human history.  

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