cease not to guard the flock itself with the utmost care and diligence from imminent dangers, lest through our negligence the sheep may perish, which were redeemed by the most precious blood of our Lord Jesus Christ. But although those matters which appertain to lay open the truth of faith and to confute the heresies of modern times were so enucleated and defined in the œcumenical and general Council of Trent, by the influence of the grace of the Holy Ghost, that it is now easy for each person to distinguish sound and Catholic doctrine from that which is false and spurious; yet, whereas the reading of books published by heretics is wont not only to corrupt mere simple men, but also to lead learned and erudite men into various errors and opinions, foreign to the truth of the Catholic faith, for this matter, also, we deemed it necessary to provide.
But, knowing that the fittest remedy for that evil was, if an index or catalogue of the books which are either heretical, or suspected of heretical depravity, or at least, are injurious to morals and piety, were drawn up and published, we referred that matter to the sacred Synod of Trent: this [synod], out of so great a number of bishops and other most earned men, chose for drawing up that index many prelates distinguished as well for learning as judgment, from nearly all nations. They, indeed, perfected that index by God's help, not without the greatest labour and much watching; certain most distinguished theologians also being called in to the council. But, the council being over, when, in pursuance of the decree of the synod itself, that index had been presented to us, so that it should not be published before it had been approved by us, we delivered it to certain most learned and approved prelates, to be read over most carefully, and to be examined, and we ourselves read it.
When, therefore, we had ascertained that it had been drawn up with great study, keen judgment, and long care, and besides, most conveniently digested; we, desiring to consult for the salvation of souls, and for that reason to take care that no books and writings of any kind, which are disapproved in it either as heretical, or as suspected of heretical depravity, or as detrimental to piety and purity of morals, or at least, as requiring any correction, should here-
