It was in fact not until nearly three fourths of a century after Gutenberg, when the leaders of the Reformation were utilising the printing-presses of Wittenberg for the spread of the Protestant heresies, that the ecclesiastics became aroused to the perils that the new art was bringing upon the true faith and upon the authority of the Church. If the people were to be protected against the insidious influence of the new heresies, it was absolutely essential that some system should be instituted under which the productions of the printing-press could be supervised and controlled. The more active and far-reaching the operations of the printers, the greater the necessity for the watchful supervision of their work, and the greater at the same time the difficulty in making such supervision complete and effective. The requirement was met by the institution of a system planned to permit no books to reach the public that had not been passed upon and approved by ecclesiastical examiners appointed for the purpose. To this end, the production and the circulation of any literature not so approved were stamped as constituting a misdemeanour of the most serious character, one that might, under certain circumstances, become the final sin against the light, the offence against the Holy Ghost. The German historian Pütter says[1]: “As a result of the great facility brought about in the production of books by the invention of printing, there came to be anxiety on the part of the authorities lest teachings destructive of religion or morality, or inimical to the interests of the State, should be given to the public. On this ground, the conclusion was in all countries promptly arrived at that no production should be permitted to come into print that had not been passed upon and approved by an officially instituted censorship, and that no printing-offices should be established excepting under proper license and effective supervision.”