Increased presence of Christians in the Levant during the Middle Ages
Development of military orders
Polarization of the East and West based on religious differences
Increased role and prestige of the popes and the Catholic Church in secular affairs
Souring of relations between the West and the Byzantine Empire leading to its destruction
Increase in the power of the royal houses of Europe
Stronger collective cultural identity in Europe
Increase in xenophobia and intolerance between Christians and Muslims, and between Christians and Jews, heretics and pagans
Increase in international trade and exchange of ideas and technology
Increase in the power of such Italian states as Venice, Genoa, and Pisa
Appropriation of many Christian relics to Europe
Use of a religious historical precedent to justify colonialism, warfare and terrorism