The Second Crusade began when the Muslims recaptured Edessa. The Second Crusade was announced by Pope Eugenius III in 1145. Four key participants in the Second Crusade were King Louis VII, Conrad III, and Bernard of Clairvaux. Conrad's poorly disciplined troops created tension in Constantinople, where they arrived in September . The downfall of the Second Crusade had many reasons. One being poor strategic planning. The Second Crusade ended in July of 1148 .

Due to St. Bernard's popularity they had him write a letter promoting it. In it he says "God hath commanded me. Slay them not, lest my people forget."
He also says that when he gets enough troops "all Israel shall be saved".

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