Crusades
Pope Innocent III started the Fourth Crusade in 1202. His plan was to attack the Holy Land through Egypt. To do this, he needed a fleet of ships. The Venetians agreed to build ships and train sailors for the crusade. The Venetians then changed the goal of the crusade, and went to the Christian city of Constantinople, where they tried to place a Byzantine exile on the throne. After a series of misunderstandings and outbreaks of violence, the city was sacked in 1204.