The Deviations of the Fourth Crusade was a series of events that took place in the 13th century and witnessed a significant departure from its original objectives. It began in 1202, led by Catholic crusaders, with the main aim of reaching Jerusalem and reclaiming it from the Muslims. However, the campaign deviated greatly from its planned course. Instead, the Crusaders launched an attack on the city of Zara in Spain and then redirected their efforts towards Constantinople, turning against the Byzantines and contributing to the fall of the city in 1204. This provoked strong criticism from the Catholic Church and caused considerable outrage.