a. On July 16, 1054, Patriarch of Constantinople Michael Cerularius was excommunicated, starting the “Great Schism” that created the two largest denominations in Christianity—the Roman Catholic and Eastern Orthodox faiths.
b. The Great Schism and other crises weakened the church's power by causing people to lose faith in the sanctity and reputation of the church, by physically removing the pope from Rome, and by creating a variety of problems that obstructed the pope's physical duties in Rome.
