“Too much of a good thing can end up being a bad thing.” During the period between 500 and 1500 AD many civilizations were progressing. Unfortunately, there have also been many empires that have progressed too far, making them unsustainable and failing. However, if they fall, it is usually for a larger reason. Whether it was an Empire at odds over religion, with weak leadership, or with uninhabitable geography, when civilizations like the Mongol Empire, the Roman Empire, or the Islamic Empire grew too large or too large, they collapsed. For a civilization to be sustainable it must have a great leader and ways of communicating. Without these qualities, ruling an empire is nearly impossible. The Mongol Empire was ruled by Genghis Khan, which meant universal ruler. Although the Mongols were “successful in raids and clan warfare,” they failed to govern the people because they did not enforce sufficient rules. In fact, Khan did not know any of the people he ruled. He employed foreigners rather than Chinese as high government officials because he believed they were trustworthy since they had no local loyalties. This angered many people, so when Khan died, the Yuan Dynasty began to fade away and rebellions broke out leading to the fall of his empire. With so many people in the Mongol Empire, not everyone spoke the same language. The Roman Empire also had problems with these concepts. Diocletian believed that the empire had become too large and too complex for a single ruler. The empire was divided into two parts: the Greek-speaking East and the Latin-speaking West. This made communication between empires extremely difficult. The Islamic Empire had to cope with about a quarter to half of its population dying from the Black Death, even... focus of article......Atic Studies, "The Mongols in World History". Accessed March 25, 2014 http://afe.easia.columbia.edu/mongols/conquests/conquests_4.htm Diamond, . “Ted” Last modified February 2003. Accessed March 25, 2014. http://www.ted.com/talks/jared_diamond_on_why_societies_collapse University of Wisconsin, last modified September 25, 1998. Accessed March 25, 2014. http://www.uwgb .edu/dutchs/westtech/xmongol.htm.National Geographic, “Steppe.” Accessed March 25, 2014. http://education.nationalgeographic.com/education/encyclopedia/steppe/?ar_a=1 .National Geographic, “National Geographic Atlas of the World.” Accessed March 25, 2014. http://travel.nationalgeographic.com/travel/countries/mongolia-facts/ .Beck, Roger B. Interaction Models of World History. Evanston, IL:McDougal Littell, 2007.http://www.bellbookandcandlepublications.com/greenwoodsvillage/gor/islam.php