The reason for the emergence of the Crusades is the call for help confront the turkish treat by the Byzantine Emperor Alexius Comnenus I who sent it to Papa Urban II. In November 1095, in the Council of the Clermont, Pope invited Western Christians to help Byzantium and recapture Holy Land from Muslims. Thus, several Crusades lasted from 1095 to 1291, between the Christians and the Muslims primarily for the Holy Land. In addition to the battles for Jerusalem, there were also fighting for several more cities that were of strategic importance in Palestine, as far as defensive positions, supplies, and ports were concerned. Although Jerusalem was the main point of the wars during these campaigns was under the authority of Christians, the final result would be that Jerusalem was again under the control of the Muslims.
The answer is: (2)