Pope Urban II was forced to wander Europe for most of his papacy because the German emperor Henry IV had installed an anti-Pope in Rome. To win support for his cause, Urban began inciting the people of Europe to reclaim the Holy Land from Islam in AD 1093, claiming participants would automatically be absolved of all their sins. His appeal drew wide support from every echelon of medieval European society, and very rapidly grew into something beyond his control: the First Crusade.
In 1098 the Franks took Antioch from the Turks; in another year Godfroi de Boullion captured Jerusalem, becoming the first King of Jerusalem since biblical times.
The Middle East remained in the control of Christians until 1291 when the Muslim prince Khalil retook the last Christian outpost, Acre. Amongst other things, the First Crusade gave rise to the Knights Templar and many of the legendary heroes of medieval Europe, including Godfroi de Bouillon (see above). The theme of the Holy Grail did not make its appearance in literature until after the advent of the First Crusade.