-series of religious wars between Christians and Muslims
-set the stage for several religious knightly military orders
-led to an increased presence of Christians in the Levant during the Middle Ages
-increased role and prestige of the popes and the Catholic Church in secular affairs
-an increase in xenophobia and intolerance between Christians and Muslims, and between Christians and Jews, heretics and pagans
-the use of a religious historical precedent to justify colonialism, warfare and terrorism
