Jerusalem is a city scared to Jews, Christians and Muslims. The Muslims captured the city in days of Hazrat Umar, but the Arabs usually allowed everyone to visit the city and thousands of Christians used to visit the city every year to see the holy places where Jesus Christ lived his life. However, the Christians from Europe have to travel a long distance, passing through the Anatolia and Syria in order to reach the city. The regional kings of these lands especially the Turks were not as friendly to the Christians as the generous Abbasids had been in the past. Pope Urban II, the religious leader of the Christians declared in 1095 AD the Christians must capture Jerusalem from the Muslims. Thousands of Christians from all over the Europe formed an army, and this army marched through Anatolia and other Muslim lands, defeating the local rulers and finally captured the Jerusalem in 1099 AD. They massacred all the Muslims and Jews living there, and the news of their cruelty shocked the entire Muslim world. However regional kings were too busy fighting each other and none of them was strong enough to take back Jerusalem. One of them, Nuruddin Zingi, who was brave and capable, died too soon.
A great leader in Muslim history Saladin Ayyubi captured Jerusalem from Christians in 1187 AD. He allowed the civilian Christians to leave the city peacefully. After this Christians called many Crusades on Jerusalem but all are failed.