Military of the Mongol Empire

During the Mongol invasions and conquests, which began under Genghis Khan in 1206–1207, the Mongol army conquered most of continental Asia, including parts of West Asia, and parts of Eastern Europe, with further (albeit eventually unsuccessful) military expeditions to various other regions including Japan, Indonesia and India. The efforts of Mongol troops and their allies enabled the Mongol Empire to become the contemporarily largest polity in human history.

Source: Wikipedia — Military of the Mongol Empire (CC BY-SA 4.0)