Some effects of the Crusades were:an increased presence of Christians in the Levant during the Middle Ages.a polarization of the East and West based on religious differencesthe increased role and prestige of the popes and the Catholic Church in secular affairsan increase in the power of the royal houses of Europea stronger collective cultural identity in European increase in xenophobia and intolerance between Christians and Muslims, and between Christians and Jews, heretics and pagansan increase in international trade and the exchange of ideas and technologythe use of a religious historical precedent to justify colonialism, warfare and terrorism