Today the modern middle-east and the Muslim, Islamic world and religion still reel from the events of the (Christian) Crusades. These historical events and battles against Islam, but also the minority of Jews living at the time in the Holy lands. These events still have consequences in the Muslim mind and remain an viable influence.
Wars today, Jihad have all a remaining influence in the political, tribal affliliation and their determination to rid western Christian influence over them, this includes the current wave of so called democracy.
During the 11th century European clergy propagated a great Crusade to defend Christian pilgrims in the Holy lands, from attacks by bandits, tribes men and Muslims. This move made by the Roman Catholic Church of the day, was done in an early attempt to unify Europe. Romans 3:23,
Ask me and I will tell you! 