In 1206, Genghis Khan, a fierce tribal chieftain from northern Mongolia, began to take over the world. The khan's ruthless tactics and loyal horde swept across Asia. A series of successful forays in Hungary and Poland made even Europe seem within reach of conquering.
But this wave of victories in Europe suddenly ended. As soon as the Mongols set their sights set on Austria, they abruptly returned to Asia. What was it that stopped the Mongol hordes?