A. =In the Græco-Roman and Græco-Byzantine Period, under Ancient Classical Forms of Civilization.= _First Section_, A.D. 70 to A.D. 323,--down to the final victory of Christianity over the Græco-Roman paganism; the Post-Apostolic and Old Catholic Ages. _Second Section_, from A.D. 323 to A.D. 692,--down to the final close of œcumenical development of doctrine in A.D. 680, and the appearance of what proved a lasting estrangement between the Eastern and the Western Churches in A.D. 692, which was soon followed by the alliance of the Papacy with the Frankish instead of the Byzantine empire; the Œcumenico-Catholic Church, or the Church of the Roman-Byzantine Empire. _Third Section_, from A.D. 692 to A.D. 1453,--down to the overthrow of Constantinople. Languishing and decay of the old church life in the Byzantine Empire; complete breach and futile attempts at union between East and West. The Church of the Byzantine Empire. B. =In the Mediæval Period, under Teutono-Romanic Forms of Civilization.= _First Section_, 4-9th cent.--from the first beginnings of Teutonic church life down to the end of the Carlovingian Age, A.D. 911. The Teutonic Age. _Second Section_, 10-13th cent.--down to Boniface VIII., A.D. 1294; rise of mediæval institutions--the Papacy, Monasticism, Scholasticism; Germany in the foreground of the ecclesiastico-political movement. _Third Section_, the 14-15th cent.--down to the Reformation in A.D. 1517; deterioration and collapse of mediæval institutions; France in the foreground of the ecclesiastico-political movement. C. =In the Modern Period, under the European Forms of Civilization.= _First Section_, the 16th cent. Age of Evangelical-Protestant Reformation and Roman Catholic Counter-Reformation. _Second Section_, the 17th cent. Age of Orthodoxy on the Protestant side and continued endeavours after restoration on the side of Catholicism. _Third Section_, the 18th cent. Age of advancing Illuminism in both churches,--Deism, Naturalism, Rationalism. _Fourth Section_, the 19th cent. Age of re-awakened Christian and Ecclesiastical life. Unionism, Confessionalism, and Liberalism in conflict with one another on the Protestant side; the revival of Ultramontanism in conflict with the civil power on the Catholic side. In opposition to both churches, widespread pantheistic, materialistic, and communistic tendencies. § 4. SOURCES AND AUXILIARIES OF CHURCH HISTORY.[1]