What were the causes, course, and consequences of both the Crusades and the broader expansion of Christianity?

The Crusades of the eleventh and twelfth centuries were the most obvious manifestation of the papal claim to the leadership of Christian society. The Crusades were wars sponsored by the papacy for the recovery of the holy city of Jerusalem from the Muslims. The enormous popular response to papal calls for crusading reveals the influence of the reformed papacy and the depth of religious fervor among many different types of people. The Crusades also reflected the church’s new understanding of the noble warrior class, for whom war against the church’s enemies was understood as a religious duty. The word crusade was not actually used at the time and did not appear in English until the late sixteenth century. It means literally “taking the cross,” from the cross that soldiers sewed on their garments as a Christian symbol. At the time people going off to fight simply said they were taking “the way of the cross” or “the road to Jerusalem.”