When Chinggis Khan (ca. 1162–1227) was born, the Mongols were just another nomadic group roaming the Central Asian grasslands. A hundred years later, they ruled a vast empire that spanned the width of Asia, from China’s Pacific coast to the Middle East. This accomplishment owed much to the Mongols’ extraordinary military prowess. Under the leadership of Chinggis Khan and his successors, mounted Mongol armies struck at their enemies with astonishing speed and ferocity. Faced with such an opponent, many of their would-be foes chose to surrender without a fight. Skill in battle, however, was not the only explanation for the Mongols’ achievement. Once the Mongols had conquered a territory, they proved adept at maintaining control of their new lands, allowing existing institutions and elites to stay in place as long as Mongol rule was not resisted and tribute was paid. Finally, the Mongols embraced diversity. They were interested in the beliefs and ideas of other peoples and did not seek to impose religious and cultural homogeneity on their empire. As you read the documents included in this feature, think about the foundations and nature of Mongol rule. How did the Mongols conquer and control their large and diverse empire?