Which Crusade do you think was the least successfulwhy?

The Fourth Crusade (1202-1204) is often considered the least successful due to its diversion from the original goal of reclaiming Jerusalem. Instead of targeting the Holy Land, the Crusaders ended up sacking Constantinople, a Christian city, which deepened the schism between the Eastern and Western churches and weakened the Byzantine Empire. This misdirection not only failed to achieve its religious objectives but also resulted in significant political and cultural ramifications that affected Christian relations for centuries.