The origin of the Crusades is rooted in political upheaval. From the mid-7th century to the mid-10th century CE, Islam gradually expanded (Riley-Smith 1). Half of the Christian world was conquered by Arab armies. This included countries in which Christianity had been established for centuries, such as Egypt, southern France, southern Italy, Sicily, Spain, Syria, and Turkey (Riley-Smith 2) . By the end of the 10th century, Europe and the Middle East were divided into hemispheres of Christian and Muslim influence. Christian pilgrims from Europe regularly visited Muslim-controlled Jerusalem. These pilgrimages were very popular. Christians viewed pilgrimage as a major act by which a person could reduce their exposure to the tortures of purgatory after death (Asbridge 21). Islamic forces had overwhelmed the Iberian Peninsula in 711 CE. The advance was so strong that only the power of Charlemagne's grandfather, Charles the Hammer, could turn them from the borders of France and the heart of Latin Christendom (Asbridge 17). The Muslims left the Christians only a thin slice of territory in the north. The kingdoms of Western Europe were loosely described as "feudal" ("Crusades"). Although the Latin states were still behind other civilizations in the Mediterranean basin, Western Europe had accumulated significant power by the 11th century ("Crusades"). ").The First Crusade was preached by Pope Urban II on November 27, 1095 in Clermont, France. In this sermon, Pope Urban II repackaged the concept of “sanctified violence” into a devotional format that was familiar, compelling, and popularly appealing (Asbridge 37). The pope preached a sermon of salvation to Christians... middle of paper ...... Online encyclopedia. " Encyclopedia - Britannica Online Encyclopedia. Web. March 25, 2011. .Foster, M. "Antioch - A Brief History of the Crusades." Medieval Crusades Splash/Home Page. Web. March 25, 2011. .Hickman, Kennedy. "Siege of Jerusalem - Crusades Siege of Jerusalem 1099." Military History - Warfare Through the Ages - Battles and Conflicts - Weapons of War - Military Leaders in History. Web. March 25, 2011. Riley-Smith J. Oxford Illustrated History of the Crusades . Oxford University Press, Oxford, pp. 1-2, 2001. "Siege of Nicaea, May 14. -June 19, 1097." Encyclopedia of Military History on the Web. Web. March 25. 2011. .