Mongol

In the 13th Century, Mongols under Genghis Khan conquered and ruled over Eastern Europe and most of Asia, establishing a Mongolian dynasty in China. They reportedly reached Vienna, Poland and Egypt. After the death of Genghis' successor in 1241 the military leaders returned to Mongolia to fight over the leadership. This helped stop the expansion and lessened the power of the armies.

In 1260, Genghis' grandson, Kublai Khan, became leader and proceeded to reconquer China to create history's largest empire. Marco Polo claimed to have visited his court. In the 14th century the Mongolian power began to wane, losing territories throughout the empire.

References:

• Creative Anachronist about the Mongols
• The Red Kagnate (Inter-Club Mongol reenactors)