The triumphant advance of Muslim armies across the inter-connecting landmass of Asia, Europe and Africa brought into the Islamic Empire large masses of people who were previously Christian, Zoroastrian, Buddhist or Hindu. Conversion to the new faith was slow. The conquering Muslims left the people of the territories alone as long as they paid the protective tax, jizya and did not interfere with...

Civilizations collide when the transcendental values that govern them are used to define identity. During the Crusades, the Christian belief that God was immanent in the person of Jesus Christ collided with the Islamic vision that God is transcendent. For the Christian world all that was holy and venerable was embodied in the Cross of the Holy Sepulcher on which Jesus is believed to have been...