John Henry Newman, An Essay in Aid of a Grammar of Assent:

“For let it be observed first, that all knowledge of the Latin classics comes to us from the medieval transcriptions of them, and they who transcribed them had the opportunity of forging or garbling them. We are simply at their mercy; for neither by oral transmission, nor by monumental inscriptions, nor by contemporaneous manuscripts are the works of Virgil, Horace, and Terence, of Livy and Tacitus, brought to our knowledge. The existing copies, whenever made, are to us the autographic originals. Next, it must be considered, that the numerous religious bodies, then existing over the face of Europe, had leisure enough, in the course of a century, to compose, not only all the classics, but all the Fathers too. The question is, whether they had the ability. This is the main point on which the inquiry turns, or at least the most obvious; and it forms one of those arguments, which, from the nature of the case, are felt rather than are convertible into syllogisms. Hardouin allows that the Georgics, Horace’s Satires and Epistles, and the whole of Cicero, are genuine: we have a standard then in these undisputed compositions of the Augustan age. We have a standard also, in the extant medieval works, of what the thirteenth century could do; and we see at once how widely the disputed works differ from the medieval. Now could the thirteenth century simulate Augustan writers better than the Augustan could simulate such writers as those of the thirteenth? No. Perhaps, when the subject is critically examined, the question may be brought to a more simple issue; but as to our personal reasons for receiving as genuine the whole of Virgil, Horace, Livy, Tacitus, and Terence, they are summed up in our conviction that the monks had not the ability to write them. That is, we take for granted that we are sufficiently informed about the capabilities of the human mind, and the conditions of genius, to be quite sure that an age which was fertile in great ideas and in momentous elements of the future, robust in thought, hopeful in its anticipations, of singular intellectual curiosity and acumen, and of high genius in at least one of the fine arts, could not, for the very reason of its pre-eminence in its own line, have an equal pre-eminence in a contrary one. We do not pretend to be able to draw the line between what the medieval intellect could or could not do; but we feel sure that at least it could not write the classics. An instinctive sense of this, and a faith in testimony, are the sufficient, but the undeveloped argument on which to ground our certitude.”