In 1076 the Muslims had conquered Jerusalem, an act that angered Christians. One Christian, the ruler of the Byzantine Empire, Alexius I of Constantinople, was fearful that the Muslims would try to conquer his lands. In the Spring of 1095 he sent envoys to ask the Pope for help.
On 27th November 1095 Pope Urban II made a speech to the Council of Claremont in France. He called upon Christians to “..persuade all people of whatever rank, foot-soldiers and knights, poor and rich, to carry aid promptly to those Christians and to destroy that vile race from the lands of our friends.
All who die by the way, whether by land or by sea, or in battle against the pagans, shall have immediate remission of sins.” (taken from the recorded version of the speech by Fulcher of Chartres)
Almost immediately people from all walks of life began preparing to make the journey east. Some went because they wanted to recapture Jerusalem for the Christians, others went because they had committed sins and saw this as a way to gain forgiveness and others believed they would find great riches in Jerusalem.
Many people died along the long overland route from France to the assembly point of Constantinople but by 1097 those that had survived the journey had gathered ready for the battle against the Muslims. The crusaders made their way from Constantinople through modern day Turkey towards their first target which was Antioch. Antioch was heavily protected and after a seven-month long siege the city fell.
Jerusalem was the next target and the attack on Jerusalem began in the Summer of 1099 and in July 1099 the city was recaptured.