The Crusades were just a war waged over power, fear, and interest. The purpose of the Crusades was to recapture the Christian "Holy Land" from the Muslims, Arabs, and even the Turks. The Crusades were stirred up and sponsored by the papacy. "It is the will of G-d", claimed Pope Urban II. His statement was not the only reason as to why the majority of the Christian population decided to engage in war against the nonbelievers. Pope Urban II's statement seems more like an excuse to make the war seem "just" and rightful in the name of G-d.
The Crusades were expeditions undertaken in fulfillment of a solemn vow, to deliver the Holy Land from Muhammedan tyranny. By the late 11th century, the leaders of the Byzantine Empire the West for help, particularly to Pope Gregory VII. After hearing this, he planned to make an expedition to the east in support of the Byzantine Emperor, but was preoccupied by investiture controversy with the Holy Roman Emperor Henry IV. Finally, Pope Urban II gave his sanction to those nobles who were inclined to respond. In Clermont, he gave a speech, which caught the attention of the west. In his speech, he included all the motivations needed for the people to participate in the Crusades, and most of these reasons were not because it was 'God's will', but promises of secular things such as more land, wealth, and power.
"It is the will of God", is what Pope Urban II said himself, but he definitely had other things in mind. Since the Greek Church of Byzantium and the Roman Church of the West were split by a theological disagreement, Urban believed that the Crusades would lead to a strong Roman influence in Greek territories, and would eventually lead to the reunion of both churches. Urban also hoped that if he called for an expedition to the East, carried out under papal leadership and his noblemen supporters, this would boost his position in the ongoing Investiture Controversy wi...