Mongol Conquest of Yuan Dynasty. The mighty Mongolian Empire was founded by Tiemuzhen, who initially unified all tribes of the Mongolian minority and was honored as Genghis Khan (meaning the ruler of the world). Since then, the Genghis Khan led his invincible army to start a large-scale offensive into the outside World. The first military target was Xixia which was located in the middle and western areas of China and in 1205, 1207 and 1209, the Mongolian army launched three massive invasions. Under such military threat, the helpless Xixia was forced to pay tributes to the Mongol and sue for peace.