The Crusades were a series of religious wars sanctioned by the Latin Church in the medieval period. The most commonly known Crusades were the campaigns in the Eastern Mediterranean aimed at recovering the Holy Land from Muslim rule, but the term "Crusades" is also applied to other church-sanctioned campaigns, such as the crusade against the Cathars and the Baltic Crusades. These were fought for a variety of reasons including the suppression of paganism and heresy, the resolution of conflict among rival Roman Catholic groups, or for political and territorial advantage. At the time of the early Crusades the word did not exist, only becoming the leading descriptive term around 1760.
In 1095, Pope Urban II called for the First Crusade in a sermon at the Council of Clermont. He encouraged military support for the Byzantine Empire and its Emperor, Alexios I, who needed reinforcements for his conflict with westward migrating Turks colonizing Anatolia. One of Urban's aims was to guarantee pilgrims access to the Eastern Mediterranean holy sites that were under Muslim control but scholars disagree as to whether this was the primary motive for Urban or those who heeded his call. Urban's strategy may have been to unite the Eastern and Western branches of Christendom, which had been divided since the East – West Schism of 1054 and to establish himself as head of the unified Church. The initial success of the Crusade established the first four Crusader states in the Eastern Mediterranean: the County of Edessa, the Principality of Antioch, the Kingdom of Jerusalem and the County of Tripoli. The enthusiastic response to Urban's preaching from all classes in Western Europe established a precedent for other Crusades.
