They themselves were shamanists, believing in nature spirits, but since their religion was tied to the land from which they came, they didn't expect new people to adopt it, and they didn't ask them to. So you could find Muslims and Buddhists and Christians and people of any other religion you can think of prospering throughout the Mongol Empire. And it's that kind of openness that has led historians to go back and reevaluate the Mongols, seeing them as kind of a precursor to modernity. But there is another side of the story that we should not forget, so here are five reasons why the Mongols might not be so great. One, here is Genghis Khan's definition of happiness. The greatest happiness is to vanquish your enemies, to chase them before you, to rob them of their wealth, to see those dear to them bathed in tears, to clasp to your bosom their wives and daughters. 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.