Where Jonathan Riley-Smith provided an overview of crusading as a movement over many centuries, Jonathan Phillips looks closely at one particular crusade, with an eye toward answering the question of why an expedition intended to take Jerusalem and other sites in the Holy Land wound up instead besieging, conquering and sacking Constantinople. Apparently this was an important question for quite a number of people over a long period of time, but given how many other crusades either strayed far afield from Jerusalem or were directed against fellow Christians in France, Italy, and parts of the German Empire, it’s not all that surprising that at some point crusaders would fight against Byzantium. Indeed, given previous relations between Greeks and crusaders that ranged from grudging passage to active attacks and subversion, it might be more surprising that the two parts of Christendom had not come to blows earlier, not least because they regarded each other as schismatics who had turned away from the true faith and thus, by some measures, worse than actual infidels.
The short version of why the Fourth Crusade wound up at the gates of Constantinople is that one thing led to another, and that choices the leaders made at early stages of the crusade both foreclosed other options and increasingly committed the crusaders to war on the Bosporus. Phillips of course tells a longer version, setting the stage with an overview of crusading in general, what the first three crusades had achieved, and what led to the preaching of a fourth at that particular time. Discussions of the preaching lead naturally into explanations of why leadership fell to men such as the Count of Flanders and the Marquis of Montferrat rather than the kings of England and France. First and foremost, the kings could not set aside their quarrels, even for such a cause as the recovery of Jerusalem. Second, the gap in resources between the prosperous counts and their nominal overlords was not as great in the late 1100s and early 1200s as would later be the case. Regional leaders could mobilize forces for crusades that were as strong as royal contingents. Third, many of these high nobles came from families that had strong crusading traditions, and they thus felt honor-bound to match the deeds of their forbears, or at least to make the attempt.
Two aspects of medieval politics and warfare that come through clearly in The Fourth Crusade are the immense amount of lead time involved and the wild uncertainty. Preparations for a new crusade began soon after the election of Innocent III as pope in 1198; the men of the Fourth Crusade arrived at their rallying point in Venice four years later, in the summer and autumn of 1202. Count Thibaut of Champagne, who had been expected to be one of the leaders of the crusade, died in late May 1201 before he had even mustered his followers, much less begun his way toward the Holy Land. Leaders tried to plan years advance, with little idea of what resources would be available to them, or whether key people would even be alive.









