Explain the dynamics behind the Christian Crusades and their consequences

What will be an ideal response?

After the Normans effectively pushed the Muslims out of the Mediterranean Sea, life began to settle in Europe and people enjoyed some degree of security. In this atmosphere, religious idealism gave way to the Crusades. The Byzantine emperor had pressed the Catholic Church to aid in delivering the East from the Muslim Turks, who were threatening the Byzantine Empire and denying Christian pilgrims access to the Holy Land. Following a fiery sermon by Pope Urban II in 1095, thousands of laymen and clergy "took up the Cross" and marched across Europe to the Byzantine East. Well before reaching their destination, a combination of avarice and religious fervor inspired some of the Crusaders to plunder the cities along the Rhine, robbing and murdering all "enemies" of Christ. It soon became apparent that the material benefits of the Crusades outweighed the spiritual ones. Aside from such economic advantages as those enjoyed by individual Crusaders and the Italian city-states, the gains made by the seven major Crusades were slight. By 1291, all recaptured lands, including the city of Jerusalem, were lost again to the Muslims.
Despite their failure as religious ventures, the Crusades had enormous consequences for the West: the revival of trade between East and West enhanced European commercial life, encouraging the rise of towns and bringing great wealth to the Italian cities of Venice, Genoa, and Pisa, which would lead to the Italian Renaissance. Political power in the embryonic nation-states of England and France were consolidated and centralized. Further, renewed contact with Byzantium promoted an atmosphere of commercial and cultural exchange that had not existed since Roman times. Luxury goods, such as saffron, citrus, silks, and damasks, entered Western Europe, as well as all of the Arabic translations of Greek manuscripts and influential Islamic literature.