The document discusses the origins and events of the First Crusade. It explains that Jerusalem was an important religious site for Christians, Muslims, and Jews. In 1079, the Seljuk Turks took control of Jerusalem and prevented Christian pilgrimage. In 1095, Pope Urban II called for the First Crusade to help Christians in the Holy Land. Over 60,000 men, women, and children from Europe embarked on the journey, which took over 3 years and resulted in thousands of deaths. In 1099, the crusaders finally reached Jerusalem and massacred its Muslim and Jewish inhabitants after a month-long siege.