After unifying the Mongols, Genghis Khan went on to conquer all of China. He breached the Great Wall, laid waste many cities along the way, and captured the capital. However, Genghis Khan was not a tyrant. He let the Chinese live as they had – there was no pressure to change their customs or persecution of their religion.
Now that the Chinese were conquered, Genghis Khan turned his attention to trade. When the Sultan of Persia killed his ambassadors and refused to trade, Genghis Khan went to war yet again. He conquered almost all of West Asia, expanding the boundaries of the Mongol Empire until it covered almost all of Asia.
After restoring the trade route in the west, Khan returned to his home in East Asia, only to find the people in China had revolted. He stopped the revolt, and was finally returning home when he fell ill and died. Thus ended the reign of Genghis Khan, one of the greatest rulers the world has ever seen.