Using the contemporary chronicle of Rashid al-Din as a guide, turn to the history of Mongol rule in Persia and the Middle East. An important element of the story is the clash of religions in a region that was becoming increasingly Muslim. A good example is the Mongol ruler of Persia, Oljeitu, who was raised as a Christian, converted to Buddhism, later to Sunni Islam, and then to Shi’a Islam.