A Crusade Diverted

Pope Innocent III called the Fourth Crusade in 1202 with Egypt as its intended target, reasoning that Jerusalem could be more securely held once Egypt, the center of Ayyubid power, was neutralized. The crusade's leaders contracted with Venice for a fleet to carry a projected army of thirty three thousand men, and Venice built the ships at considerable cost on that expectation; far fewer crusaders actually arrived at Venice to embark, leaving the army unable to pay what it owed.

Venice proposed a way to work off the debt: the crusaders would help it recapture Zara, a Christian city on the Adriatic that had rebelled against Venetian rule and placed itself under the Hungarian crown. Innocent III forbade the attack and threatened excommunication, but the crusade's leadership went ahead regardless, and Zara was sacked in November 1202. Innocent excommunicated the Venetians and, more reluctantly, the crusaders, though he later lifted the sentence on the crusaders themselves while it remained on Venice. Innocent's own legate, present with the army, had no real power to overrule the crusade's secular leadership once the debt to Venice made the diversion to Zara appear unavoidable to the barons who actually commanded it, a foretaste of how little control the papacy would keep over the campaign that followed.