Reconstructing the motives of Crusaders and the founders of the Crusader States is a complex task. Two general theories that emerged are the Marxist-influenced materialist theory and an explanation that rests on religious idealism. Two important preliminary points need to be addressed. First, the desire for material gain and devotion to religious idealism are not mutually exclusive; they could and often did coexist, and they strengthened rather than weakened one another. Second, “crusaders” are referred to as the large assortment of people drawn from the entire spectrum of social backgrounds and economic standing. One cannot assume that what motivated priests and paupers inspired castellans (castle wardens) and dukes. For that matter, one cannot assume that what motivated one count necessarily motivated another count. Venetian motives most likely clashed with all of the above. Backgrounds and interests varied, and therefore motives for committing oneself to such a venture did as well.
The materialist argument used to be much more popular and influential. It sprang from a confluence of two trends: the Marxist approach, which saw the root for all historical causation as being centered on production and attempts to control it, and the positivist neo-Rankian approach, which distrusted the rhetorical explanations posterity left behind and attempted to pierce the veneer to get to “real” causes and issues. The materialist theory of the First Crusade (1096-1102) stressed the massive economic changes that were taking place in western Europe and the financial pinch they applied to all sectors of society. Primogeniture, a new approach to inheritance, began awarding property to the eldest son, leaving a mob of belligerent and land-hungry second sons to fend for themselves and to seek their fortunes. Conquest was the only real method by which the second sons could become landed, and thus the idea of staking claims in the East was attractive. The First Crusade was a “second son” venture that directed surplus members of the warrior
aristocracy to the East. The position of the poor was even worse. Since the turn of the millennium western Europe had experienced rapid population growth, an escalation of trade, and increases in the circulation of money—all of which pressed upon and strained the earlier manorial structure. These forces created a new form of “poor,” a group of itinerant laborers who had no solid place in the feudal structure. The rapid response of the poor to the summons of a man such as
Peter the Hermit is thus easy to explain. Pope Urban II mentioned the possibility of acquiring wealth while making his call for a Crusade at the Council of Clermont (1095), even if it was not the focus of his preaching campaign. That France was in the throes of crop failure and famine when the First Crusade was preached has been cited with approval and clinches the argument.