In the first several years of 13th century, Genghis Khan unified the Mongolian tribes, founding the Mongolian Empire, and led them to overcome the majority of Asia, Central Asia, Russia and center East. His armies occupied a great part of European countries, too, pregnancy to one associated with biggest empires in history. His cavalry units, specially their horse archers, were Genghis Khan's elite troops and were able, with intense but well coordinated costs, to hit terror within their enemies' hearts. 8 Unpainted numbers with horses