The Lost History of Christianity: The Thousand-Year Golden Age of the Church in the Middle East, Africa, and Asia—and How It Died

by Philip Jenkins

During the thirteenth century, the Muslim states suddenly found themselves under attack from a lethal enemy whose activities made the Western Crusades look like fleabites. The Mongol assault on the Islamic world began in 1219 when the forces of Genghis Khan attacked the Khwarezmid Empire of central Asia, taking such great cities as Bukhara and Samarkand.