Osprey's study of the Mongols' invasion of Russia. In 1221, Genghiz, Great Khan of the Mongols, ordered an armed reconnaissance expedition into Russia commanded by Sübodei Bahadur and Jebei Noyon 'The Arrow'. The consequences for the history of Europe were incalculable. The decisive Mongol victory at Kalka River, opened up vast regions of Russia and Eastern Europe to Mongol conquest. Genghiz ordered his victorious army to return eastwards, delaying the final cataclysm by a few years. Genghiz died in 1227, but within 10 years his son Ögedei ordered a return to Russia to complete the conquest. This title details the events of the dramatic Kalka River campaign.