ABSTRACT
The sixteenth century witnessed a seeking of thoroughgoing religious reforms. In striving to keep both its outer and inner integrity, the ancient Catholic Church developed two things: a system of doctrine, clarified and declared to be purged of error, and an ecclesiastical organization characterized in its own eyes by apostolicity, catholicity, unity, and holiness. The chapter describes the several steps by which these developments were brought about. Cathedrals were of three chief types: Byzantine, Romanesque, and Gothic, and this ordering of adjectives roughly corresponds to their chronological development. Monasticism grew rapidly in the Catholic Church after Christianity was made the imperial state religion. The unity of the Orthodox churches has never been really broken. Under antireligious Marxist regimes in the former Soviet Union and its eastern European allies, the Orthodox churches struggled to maintain as much autonomy as they could.
