The Fourth Crusade was marked by its diversion from its original intent of recapturing Jerusalem, leading crusaders to set their sights on Zara. In November of 1202, a group of Catholic crusaders commenced a siege against the city of Zara, which lay on the coast of the Adriatic Sea, a strategic location for further advancements. This action was particularly controversial as Pope Innocent III, who had a vested interest in the crusade, had sent letters forbidding the siege due to Zara being a Christian city, and warned of excommunication for such actions. Despite the pope's orders, the crusaders decided to go ahead, reflecting the internal conflict and moral dilemmas faced during the campaign.

Following the siege, Zara fell to the crusaders, who carried out significant acts of looting and violence against the city. The temptation of wealth, combined with political intrigue and alliances, led to this deviation from their sacred mission. The siege was not just a military action but also showcased the complex interplay of power politics, religion, and economic motivations that influenced the leaders and soldiers alike. Zara's fall marked a turning point in the Fourth Crusade, setting up further entanglements in the region.