Pope Urban II framed the Crusades as a quest to free Jerusalem and the Holy Land from infidels or unbelievers.
Pope Urban II is best known for his initiation of the First Crusade in 1096, when he started a Christian war against Muslims who have taken the Holy Land (contemporary Israel, Palestine, Jordan, Lebanon, and Syria) from Christians, and he obviously wanted those territories back. He considered Muslims heretics who needed to be dealt with.