The responsibility to remember : introduction to the historiography of Christianity -- "The law of praying is the law of believing" -- Sibling rivalry : heresy, orthodoxy, and the ecumenical councils -- The heavenly city : the Augustinian synthesis of biblical religion and Hellenism -- The development of the Medieval papacy -- Faith in search of understanding : Anselm, Abelard, and the beginnings of scholasticism -- The Medieval church -- The Reformations of the sixteenth century -- Pietism and the Enlightenment -- Challenge and response : the church in the nineteenth century -- The Christian churches since World War I.