The Mongol Empire, founded by Genghis Khan and continued by his heirs, was one of the largest and most powerful the world has ever seen. Modern China was created from the remnants of the Mongol Empire, and at its peak, this empire controlled one-sixth of the total landmass of the world. Even today, it is estimated that one in every 200 people in the world carries the DNA of Genghis Khan. The world would never be quite the same after the relatively brief reign of Genghis Khan, his children, and grandchildren.

This was an empire marked by stark and often baffling contrasts. Genghis Khan himself displayed marked tolerance for ethnic and religious diversity. He generally treated his people well, reducing taxes and promoting social care and medicine while banning torture and imprisonment. Within his empire, women were permitted to rise to the highest political and religious levels. Yet this tolerance, fairness, and diversity were combined with incredible brutality: The Mongol Empire is believed to have killed around 60 million people, more than the combined deaths from World War I and World War II. To their subjects, the Mongol emperors were leaders to be revered and respected. To the rest of the world, they were terrifying and bloodthirsty tyrants.

The beginning of the Mongol Empire is the subject of countless stories, yet there are relatively few original sources to tell us what really happened. What we have are myths and legends, a handful of confirmed facts, and expert conjecture about what must have happened. This is the story of how one man’s ambition, drive, and fervor changed the world. This is the story of the Mongol Empire.