Genghis Khan ruled between 1206 and 1227, expanding trade across Asia and into eastern Europe, enacting relatively tolerant social and religious laws, and leading devastating military campaigns that left local populations depleted and fearful of the brutal Mongol forces.
Under Genghis Khan and his son Ögedei, the Mongol Empire conquered both the Western Xia Dynasty and the Jin Dynasty to the west.
Under Genghis Khan, the Mongols, who began using catapaults and gunpowder in their invasions, conquered the Kara-Khitan Khanate and the Khwarazmian Empire.
Under Ögedei, the Mongol Empire conquered Eastern Europe. Various tactical errors and unexpected cultural and environmental factors stopped the Mongol forces from moving into Western Europe in 1241.
Möngke was generally a popular ruler of the Mongol Empire; he met debts, controlled spending, conducted a census, and protected civilians.
Kublai Khan came to power in 1260. By 1271 he had renamed the Empire the Yuan Dynasty and conquered the Song dynasty and with it, all of China. However, Chinese forces ultimately overthrew the Mongols to form the Ming Dynasty.