In the first many years of 13th century, Genghis Khan unified the Mongolian tribes, founding the Mongolian Empire, and led them to conquer the majority of China, Central Asia, Russia and center East. Their armies occupied a great element of Europe, too, pregnancy to one for the biggest empires ever. His cavalry devices, especially his horse archers, were Genghis Khan's elite troops and managed, with tough but well coordinated costs, to hit terror to their enemies' hearts.