Though there were essentially no technological inventions, no beautiful buildings or even great Mongol art, with each battle and enemy, their culture learned and absorbed something new. Under Genghis Khan’s direction, the Mongols were as ruthless about stealing and absorbing the best of each culture they encountered as they were about conquest itself. In fact, if there is one theme in his reign and in the several centuries of dynastic rule that followed, it’s this: appropriation. For not only was Genghis Khan one of the greatest military minds who ever lived, he was a perpetual student, whose stunning victories were often the result of his ability to absorb the best technologies, practices, and innovations of each new culture his empire touched. Like all reactionary, emotional assessments, this could not be more wrong. Then, not unlike his nomadic band of warriors, this terrible cloud simply disappeared from history, because the Mongols built nothing that could last. We have him and his Mongol horde traveling across Asia and Europe, insatiable, stopping at nothing to plunder, rape, and kill not just the people who stood in their way, but the cultures they had built. The legend of Genghis Khan has echoed through history: A barbarian conqueror, fueled by bloodlust, terrorizing the civilized world. In his book, Ego is the Enemy, Ryan Holiday tells the story of Genghis Khan and how his openness to learning was the foundation of his success.