The First Crusade was a military expedition launched in 1096 by European Christians to reclaim the Holy Land from Muslim control. It was sparked by a call from Pope Urban II, who urged Christians to help their fellow believers in the East. Thousands of knights and common people joined the cause, motivated by religious fervor, adventure, and the promise of forgiveness for their sins. After a long and challenging journey, the crusaders captured Jerusalem in 1099, marking a significant victory. This success led to the establishment of several Crusader states in the region, but it also intensified conflicts between Christians and Muslims, setting the stage for future crusades.