At the very beginning of the Apostolic Age the universalistic spirit of Christianity had already broken through the particularistic limitations of Judaism. When once the substantial truth of divine salvation had cast off the Judaistic husk in which the kernel had ripened, those elements of culture which had come to maturity in the Roman-Greek world were appropriated as means for giving to Christian ideas a fuller and clearer expression. The task now to be undertaken was the development of Christianity on the lines of Græco-Roman culture, or the expansion of the church’s apostolicity into catholicity. The ancient church of the Roman and Byzantine world fulfilled this task, but in doing so the sound evangelical catholic development encountered at every point elements of a false, because an unevangelical, Catholicism. The centre, then, of all the movements of Church History is to be found in the Teutono-Roman-Slavic empire. The Roman church preserved and increased her importance by attaching herself to this new empire, and undertaking its spiritual formation and education. The Byzantine church, on the other hand, falling into a state of inward stagnation, and pressed from without by the forces of Islam, passes into decay as a national church. The history of this first stage of the development of the church falls into =three periods=. The first period reaches down to Constantine the Great, who, in A.D. 323, secured to Christianity and the church a final victory over Paganism. The second period brings us down to the close of the universal catholic or œcumenical elaboration of doctrine attained by the church under its old classical form of culture, that is, down to the close of the Monothelite controversy (§ 52, 8), by the Sixth Œcumenical Council at Constantinople in A.D. 680. But inasmuch as the _Concilium quini-sextum_ in A.D. 692 undertook simply the completion of the work of the two previous œcumenical synods with reference to church constitution and worship, and as here the first grounds were laid for the great partition of the church into Eastern and Western (§ 63, 2), we prefer to make A.D. 692 the closing limit of the second period. The conclusion of the third period, is found in the overthrow of Constantinople by the Turks in A.D. 1453. The first two periods are most evidently distinguished from one another in respect of the outward condition of the church. Before the times of Constantine, it lives and develops its strength amid the oppression and persecution of the pagan state; under Constantine the state itself becomes Christian and the church enjoys all the advantages, all the care and furtherance, that earthly protection can afford. Along with all this worldly splendour, however, a worldly disposition makes its way into the church, and in exchange for its protection of the church the state assumes an autocratic lordship over it. Even in the inner, and pre-eminently doctrinal, development of the