The fidelity of the copyists, and the genuineness and integrity of ancient manuscripts, have been warmly and learnedly defended by the laborious Father Mabillon, on every occasion throughout his great work, _De Re Diplomatica_.[2] The leading motive which impelled the indefatigable author to the prosecution of the researches of which this work gives the result, seems to have been the desire to establish the genuineness and integrity of ecclesiastical, and especially of monastic charters. In the course of his inquiries, he brings forward a vast variety and amount of information relating to the modes of writing practised in the monasteries, and in the courts of the French kings, during the middle ages. These facts are of course most available in arguments that relate to the genuineness and antiquity of existing manuscripts in the _Latin_ language; but there is so much of the substance of the argument touching the genuineness of all ancient writings in the following passages, that they may well be placed before the reader. The work itself is little likely to come under the eye of those for whom this volume is intended. This learned writer says:--“Before I conclude this supplement, I think it may be proper to say something concerning the integrity and authority of ancient books, which some persons dispute. For assuredly, if the genuineness of charters and public deeds is doubted, the authority of ancient manuscripts in general is also called in question; and, if these doubts can be substantiated, it will appear that those who employ themselves in collating the printed editions of the Fathers, or other sacred books, with ancient manuscripts, spend their labour in vain. And hence, too, we must believe, contrary to the opinion of all learned persons, who think the world greatly indebted to the labours of the monks in transcribing books, that they toiled to no good purpose. Such persons, to give colour to their opinion, affirm that the existing ancient manuscripts were executed by ignorant men, whose blunders are easily perceived by the learned; and on this prejudice they have founded the decision, that manuscripts having been written, for the most part, by unskilful hands, and derived many from one, are of little avail in understanding or restoring an author.