As the history of the beginnings of the church has been treated by us under two divisions, so also the first period of the history of its development may be similarly divided into the =Post-Apostolic Age=, which reaches down to the middle of the second century, and the =Age of the Old Catholic Church=, which ends with the establishment of the church under and by Constantine, and at that point passes over into the Age of the œcumenical Catholic or Byzantine-Roman Imperial Church.--As the Post-Apostolic Age was occupied with an endeavour to appropriate and possess in a fuller and more vigorous manner the saving truths transmitted by the Apostles, and presents as the result of its struggles, errors, and victories, the Old Catholic Church as a unity, firmly bound from within, strictly free of all compulsion from without, so on the basis thus gained, the Old Catholic Church goes forward to new conflicts, failures, and successes, by means of which the foundations are laid for the future perfecting of it through its establishment by the state into the Œcumenical Catholic Imperial Church.[20] § 20.1. =The Post-Apostolic Age.=--The peril to which the church was exposed from the introduction of Judaistic and Pagan elements with her new converts was much more serious not only than the Jewish spirit of persecution, crushed as it was into impotence through the overthrow of Jewish national independence, but also than the persecution of anti-Christian paganism which at this time was only engaged upon sporadically. All the more threatening was this peril from the peculiar position of the church during this age. Since the removal of the personal guidance of the Apostles that control was wanting which only at a subsequent period was won again by the establishment of a New Testament canon and the laying down of a normative rule of faith, as well as by the formation of a hierarchical-episcopal constitution. In all the conflicts, then, that occupied this age, the first and main point was to guard the integrity and purity of traditional Apostolic Christianity against the anti-Christian Jewish and Pagan ideas which new converts endeavoured to import into it from their earlier religious life. Those Judaic ideas thus imported gave rise to Ebionism; those Pagan ideas gave rise to Gnosticism (§§ 26-28). And just as the Pauline Gentile Christianity, in so far as it was embraced under this period (§ 30, 2), secured the victory over the moderate and non-heretical Jewish Christianity, this latter became more and more assimilated to the former, and gradually passed over into it (§ 28, 1). Add to this the need, ever more pressingly felt, of a sifting of the not yet uniformly recognised early Christian literature that had passed into ecclesiastical use (§ 36, 7, 8) by means of the establishment of a New Testament =canon=; that is, the need of a collection of