A Mongol army under Genghis Khan captured Zhongdu (modern Beijing), the capital of the Jin dynasty of China. Mongol Empire: The Mongol Empire was the largest contiguous empire in history. Originating in present-day Mongolia in East Asia, the medieval empire at its height stretched from the Sea of Japan to Eastern Europe, extending northward into Siberia and east and southward into the Indian subcontinent, mounting invasions of Southeast Asia, and conquering the Iranian plateau; and reaching westward as far as the Levant and the Carpathian Mountains. May 31, 1215. Wiki link