The document provides information about the Crusades, a series of religious wars between Christians and Muslims over control of Jerusalem from the 11th to 13th centuries. It details the causes of the Crusades, including Muslim capture of Jerusalem and attacks on Christian pilgrims. Pope Urban II called for troops to defeat the Turks and retake the Holy Land. Feudal lords, knights, and peasants answered the call. The First Crusade succeeded in capturing Jerusalem but later Crusades met with defeat against Saladin and the Turks, who eventually retook the Holy Land. The Crusades declined over time due to lack of interest, defeats, and being discredited by crusades against other Christians. The Crusades had various effects