Historians like a good puzzle, so it comes as no surprise that over the centuries many have tackled the so-called “Diversion Question” of the Fourth Crusade. The question is simple enough. How did a Crusade of this magnitude veer wildly off course, ultimately conquering Constantinople, the greatest Christian city in the world? The answer, of course, is anything but simple. The intricacies of motives, errors, and miscommunications require one to understand not only the Crusade, but also the histories of the Papacy, the German Empire, Venice, and the Byzantine Empire. The sources for the Fourth Crusade are many, often contradictory, and of differing quality.