The Mongols had a great emperor that unified China named Genghis Kahn. Then after his death Kubli Kahn took over and split the empire into four regions. Each was ruled by a leader called the Great Kahn. They worked to finish Genghis Kahn's dream of conquering the World.
The Pax Mongolia was a time of peace and prosperity for the Mongols. After they had conquered their land, the empire had a time of peace, this was called the Pax Mongolia. The Pax Mongolia was like the Pax Romana for the Romans.