The Crusades were a series of military campaigns of a religious character fought from 1096 to 1291 by most of the Christian Europe against the Muslims in the Middle East. However, the Crusades were also launched against the pagan Slavs, Jews, Orthodox Christians, Albigenses, Hussites as well as against political enemies in Europe (such as the Crusade against Holy Roman Emperor Frederick II). The appeal of the Byzantine Emperor, Alexios I Comnenus to the Pope for military assistance against the Seljuk Turks resulted in the convocation of the Council of Clermont by Pope Urban II in November 1095. At the Council of Clermont, Pope Urban II called for the Crusade against the Muslims who had occupied the Holy Land and were attacking the Byzantine Empire and gave a cloth crosses to the knights to be sewn into their armor which gave the Crusades their name.
After the Council of Clermont, Pope Urban II travelled throughout France preaching and organizing the Crusade. Although he expected his call for the Crusade will be responded only by knights and warriors the majority of those who took up his call were the poor peasants without any fighting skills.
The appeal of the Byzantine Emperor, Alexios I Comnenus to the Pope Urban II is widely regarded as the immediate cause for the Crusades but the real cause for the Crusades laid in Papacy’s and Western Europe’s own interests. The Papacy saw an opportunity to establish its dominance over the Holy Land, while the Crusaders were primarily led by economic, political and social motives. The best evidence for that is the fact that the Crusaders were primarily concentrated on capturing of Palestine instead of helping the Byzantine Empire against the Seljuk Turks of Anatolia.