The Crusades were a series of military expeditions launched in the pursuit of religious goals. While the crusades were usually organized by the papacy, the military expeditions themselves were led by a mixture of nobles and monarchs, often lacking a formal leadership hierarchy. The crusades were started at the Council of Clermont where Pope Urban II called for the Christians in the west to defend their brethren in the east. This was framed as an armed pilgrimage and an act of penance through which one could earn salvation. Those who went on the crusade were said to have took the cross (sometimes literally with a cloth cross sown on their clothes) and the term crusade itself was derived from the word crucesignati which means "those signed by the cross"[1].
Most of the crusading energy was directed toward the area known as the Holy Land, as Jerusalem was considered a sacred city. Many crusades were launched with the purpose of capturing Jerusalem from the Muslims. The first crusade succeeded in capturing Jerusalem in 1099 and establishing several independent political entities in the Levant called the Crusader States. These were the Kingdom of Jerusalem, Principality of Antioch, County of Tripoli, and the County of Edessa. The crusaders' military presence in the region continued until the fall of Acre in 1291. There are generally accepted to be nine crusades to the Holy Land, but there were other crusades launched for religious reasons.