History of Christianity

====Crusade====
[[File:Map Crusader states 1135-en.svg|thumb|The [[Kingdom of Jerusalem]] and the [[Crusader states]] with their strongholds in the [[Holy Land]] at their height, between the [[First Crusade|First]] and the [[Second Crusade|Second]] Crusade (1135)|alt=image of Map Crusader states 1135]] 
After 1071, when the [[Seljuk Turks]] closed access for Christian pilgrimages and defeated the Byzantines at [[Battle of Manzikert|Manzikert]], the Emperor [[Alexius I]] asked for aid from [[Pope Urban II]]. Historian [[Jaroslav Folda]] writes that Urban II responded by calling upon the knights of Christendom at the [[Council of Clermont]] on 27 November 1095, to "go to the aid of their brethren in the Holy Land", an appeal aimed largely at those with sufficient wealth and position to subsidize their own journey.{{sfn|Folda|1995|p=141}}{{sfn|Tyerman|1992|pp=15–16}} The [[First Crusade]] captured Antioch in 1099, then Jerusalem, establishing the [[Kingdom of Jerusalem]].{{sfn|Folda|1995|p=36}}

The [[Second Crusade]] began after [[County of Edessa|Edessa]] was taken by Islamic forces in 1144.{{sfn|Fonnesberg-Schmidt|2007|p=65}} Christians lost Jerusalem in 1187 through the catastrophic defeat of the Franks at the [[Battle of Hattin|Horns of Hattin]].{{sfn|Folda|1995|p=150}} The [[Third Crusade]] did not regain the major Holy sites.{{sfn|Folda|1995|p=150}}

The [[Fourth Crusade]], begun by [[Pope Innocent III|Innocent III]] in 1202 was subverted by the Venetians. They funded it, then ran out of money and instructed the crusaders to go to Constantinople and get money there. Crusaders sacked the city and other parts of Asia Minor, established the [[Latin Empire]] of Constantinople in Greece and Asia Minor, and contributed to the downfall of the Byzantine Empire. Five numbered crusades to the Holy Land culminated in the [[Siege of Acre (1291)|siege of Acre]] in 1291, essentially ending Western presence in the Holy Land.{{sfn|Marshall|1994|p=1}} Crusades led to the development of national identities in European nations, increased division with the East, and produced cultural change for all involved.{{sfn|Kostick|2010|pp=2–6}}{{sfn|Matthews|Platt|1992|pp=192–195}}