The seventh century saw the rise of Mohammedanism when Mohammed made Mecca the center of his new cult. Believing that a new religious era had been established in 622, the year Mohammed fled for his life from Mecca, his followers carried on a militant crusade from country to country throughout the Near East. Their steady progress against all opposition resulted in the loss to the empire of Syria, Palestine, Egypt, North Africa, and Spain. A century later the tide of conquest had swept over the Pyrenees, but the Franks checked the wave of invasion at Tours in 732, saving the West for Christianity. The Eastern Empire was shorn of much of its strength. The Muslim conquests extended as far east as the frontiers of India and China.
Impact: The Empire that centered at Constantinople was so crippled that it could not hope to conquer again any part of Europe, and the patriarch of Constantinople was no longer in a position to rival the Bishop of Rome. The Eastern Church made good some of its losses by sending out missionaries like Cyril and Methodius, winning the allegiance of princes like Boris of Bulgaria and Vladimir of Russia, and asserting the authority of the patriarch of Constantinople over their realms.