ボレスワフ4世
The two main Christian forces that marched to the Holy Land in response to Pope Eugene III and Bernard of Clairvaux's call for the Second Crusade were led by Louis VII of France and Conrad III of Germany. Conrad's force included Bolesław IV the Curly and Vladislaus II of Bohemia, as well as Frederick of Swabia, his nephew who would become Emperor Frederick I. The crusade had been called after the fall of the County of Edessa on 24 December 1144. The crusaders marched across Europe and arrived at Constantinople in September and October 1147.