Answer:
The crusades started with the sermon of Pope Urban second, he urged the peasants and nobles to initiate a holy war to reclaim the holy land from Muslims. He told people that they will get Salvation, fame and wealth if they participate in the crusades. The crusaders were able to reclaim Jerusalem in 1099.
During the second crusade, Emperor Saladin and the English king Lion heart came to a compromise. It was known as the peace of Ramala. According to the Peace of Ramala, the Muslims could control the Jerusalem but the Christians would be allowed to visit the holy land. The third crusade was children's crusade as 20,000 children were sent to fight, they were without any leader. This crusade also failed. So it can be concluded that only the first crusades were successful.