The Crusades. Religion played an important part in the development of civilization in the Middle Ages.
About six hundred years after the establishment of the Christian Church, the followers of Mohammed, inspired by the faith of their leader, spread throughout Arabia, Asia Minor, and northern Africa. Early in the eighth century they came into Spain and overran most of the Iberian peninsula. The Moors, as the Mohammedans there were called, came into conflict with the Christians, and bitter warfare followed between the Cross and the Crescent.
For many years Christians from western Europe had made pilgrimages to the Holy Land for the purpose of worshiping at the tomb of Jesus, which was known as the Holy Sepulcher. This worship had been permitted by the Mohammedan Arabs who were in control of Palestine; but after the conquest of the Holy Land by the Seljuk Turks, who were more aggressive Mohammedans, worshiping at the holy places became more difficult and dangerous. The Pope appealed to the feudal lords and knights to cease fighting their Christian neighbors and combine against the infidel Turks, in a holy war for the purpose of rescuing the Holy Sepulcher.
At a meeting in 1095, Pope Urban II preached a holy war against the Turks. As a result, several religious military expeditions were organized, which continued for almost two hundred years. These expeditions are known as the Crusades. As military expeditions, they failed, for while Jerusalem was taken and held for a time by the Christians, it was recaptured by the Turks. In spite of the military failure of the Crusades, they had many important social, intellectual, and commercial effects, because the people from western Europe were brought into contact with the East. Intellectual curiosity and study were stimulated. The East had many products, such as spices, perfumes, silks, precious stones, and other articles which the West wanted. The Crusades therefore stimulated trade.
Other important results followed. Some of the knights, dukes, and kings who went on these military expeditions did not return, while some of those who did return were too poor to recover their lands. This condition gave some of the serfs an opportunity to free themselves from the feudal system. Many serfs therefore went to the towns, where, by engaging in industry and trade, they became wealthy and influential citizens. This group became known as the middle class, or the bourgeoisie. The growth of a large wealthy middle class was a powerful contributing factor to the breakdown of the feudal system.