The exact principles that guided the formation of a canon in the earliest centuries cannot be discovered. Strictly speaking there were none. Definite grounds for the reception or rejection of books were not apprehended. The choice was determined by various circumstances, of which apostolic origin was the chief, though this itself was insufficiently attested; for if it be asked whether all the New Testament writings proceeded from the authors whose names they bear, criticism cannot reply in the affirmative. The example and influence of churches to which the writings had been first addressed must have acted upon the reception of books. Above all, individual teachers here and there saw the necessity of meeting heretics with their own weapons, in their own way, with _apostolic records_ instead of oral tradition. The circumstances in which the orthodox were placed led to this step, effecting a bond of union whose need must have been felt while each church was isolated under its own bishop and the collective body could not take measures in common. Writings of more recent origin would be received with greater facility than such as had been in circulation for many years, especially if they professed to come from a prominent apostle. A code of apostolic writings, divine and perfect like the Old Testament, had to be presented as soon as possible against Gnostic and Manichæan heretics whose doctrines were injurious to objective Christianity; while the multiplication of apocryphal works threatened to overwhelm genuine tradition with a heap of superstition. The Petrine and Pauline Christians, now amalgamated to a great extent, agreed in hastening the canon-process. The infancy of the canon was cradled in an uncritical age, and rocked with traditional ease. Conscientious care was not directed from the first to the well-authenticated testimony of eye-witnesses. Of the three fathers who contributed most to its early growth, Irenæus was credulous and blundering; Tertullian passionate and one-sided; and Clement of Alexandria, imbued with the treasures of Greek wisdom, was mainly occupied with ecclesiastical ethics. Irenæus argues that the gospels should be four in number, neither more nor less, because there are four universal winds and four quarters of the world. The Word or Architect of all things gave the gospel in a fourfold shape. According to this father, the apostles were fully informed concerning all things, and had a perfect knowledge, after their Lord’s ascension. Matthew wrote his gospel while Peter and Paul were preaching in Rome and founding the church.(221) Such assertions show both ignorance and exaggeration.