The Crusades were a series of military campaigns against Syria and Egypt from 1097 to 1291. During this time Pope Urban II conducted a sermon at Clermont to call upon the Christians to liberate Jerusalem from the Muslims. His message to the nobles was to bring order to their kingdoms. He told them that this is what God wants them to do, which will expiate for their sins. Pope Urban also mentioned the distribution of money that will take place if they are successful in liberating Jerusalem from the Muslims. ?al?? ad-D?n Y?suf ibn Ayy?b was the Muslim leader who led the recapture of Jerusalem. The Crusades were a major military and religious order that played a significant role in the history of Islamic civilization, as we know it today. The Crusades affected both the Muslims and Jews alike. The apocalyptic message was to make everyone convert to Christianity because they needed to avenge the crucifixion of Christ. Today, many people in the Middle East refer to the Crusades with grief, as it was 200 years of attacks on them out of religious zealotry and blood lust. Throughout these terrible 200 years, the Europeans were able to learn about Islam in many different aspects, such as its cultural and economic benefits. Europeans were able to benefit from the Islamic economy, culture, and civilization, all while taking advantage of their knowledge. The Crusades allowed the achievement of Islamic civilization to flourish in Europe. It is interesting how the Crusaders came to the Middle East, seeking war and destruction, but left with knowledge. They were able to benefit as much as they could and brought these principles back with them to Europe. At the time Europe was suffering, and it was exactly what they needed. Thus, the Islamic world was a global center for learning, trade, and culture. With the crusades, a huge transformation of world exploration and trade exchange began to thrive. Travelling long distances forced the Crusaders to participate in shipbuilding. As they returned to the Middle East, they brought back silk, spices, perfumes, tapestries, and food such as rice, dates, and coffee. However, these resources were quite scarce, and the trade turned into journeys for exploration. Despite the ultimate defeat of the Crusaders, they were able to go back into Europe. However, Islam, unfortunately, became weakened in the process. This helped to delay the process of capturing Constantinople and made way for the Mongols to target Islam as they came in from the East. The Mongols ended up shattering the Muslim world, wishing to protect Europe, yet they ended up converting to Islam in the end. Before the Crusades, the churchmen had a negative attitude towards the military, because Jesus’ message prohibited warfare. As matters changed, the idea that “just war” was allowed came about and that is how the Crusades were justified among the Christians. The long exchange between Muslims and Christians, not only led to an exchange of goods but ideas as well. Philosophy, science, mathematics, medicine, and education were all introduced to the Christians, giving them a newfound way to look at the world. Customs of hygiene practices and public bathing was reintroduced. Medicine, literature, and poetry flourished in Europe, and the civilization continued to thrive.