ABSTRACT
Conquest in the Middle Ages was always difficult. Even the greatest kings found collecting resources complicated and persuading followers problematic, which is why it was usual to try to come to terms with the existing population. The Crusade was presented in terms comprehensible to the military leaders of Western society with their proprietorial instincts. After the triumph of the First Crusade in 1099, the crusade became an established institution of the medieval West. The papacy directed crusaders to many different places at different times. Crusading came in fits and starts, often with long intervals in between. The absence of a major effort after the failure of the Second Crusade undoubtedly helped the Islamic powers in their assault on the crusader principalities. Warfare in the Middle East was heavily conditioned by geographical and climatic factors. In general, the countryside was much emptier than in the West, and there were large tracts of desert and semi-desert.
