In the year 1562, the Council of Trent turned its attention to the question of book-trade, and, after a long discussion, appointed a committee of eighteen members to examine into the subject, and to draft a decree, together with a revised _Index_. The _Tridentine Index_ is based upon the _Index_ of Paul IV. Both devote almost their entire space to works of heresy, giving but trifling consideration to the question of immoral literature. The _Tridentine Index_ presents ten rules for guidance in the enlargement and continuation of the _Index_. It introduces also the formula _donec corrigatur_. This formula signified either a temporary or partial prohibition of a work not absolutely condemned, or a conditional permission for its continued sale, provided that, in all copies of existing editions, the condemned passages were either blotted out or corrected by pen, while in all subsequent editions they were to be omitted or modified. The fifth rule provided that all booksellers must have in their shops a list of the books which they kept on sale, such list being signed by the Inquisitor and the Bishop’s delegate; and they were forbidden to have, to sell, or to distribute any other books than those on said list, under penalty of forfeiture of the books and of such other punishment as might be ordered by the Inquisition. Under the seventh rule, one who had imported books was forbidden to give or to loan them for the reading of another, or to part with them in any way without written permission. The eighth rule provided that heirs were to submit to the authorities a list of books inherited by them, before using or parting with any of them. The ninth rule gave to Bishop and Inquisitors-General the authority to forbid within their diocese or provinces books other than those which appeared in the _Index_. This _Tridentine Index_ appears to have been recognised at once as the authoritative utterance of the Church on the subject of books, and to have been very generally circulated. It was printed in Venice by the Aldine Press, and it was printed ten times subsequently between 1564 and 1593. The whole position of the censorship of the Press, as well in Venice as in the other publishing centres of Italy, was essentially modified through the publication of the _Tridentine Index_. The coöperation or approval of the secular authority, which, in Venice at least, had kept in its own hands the nominal control of the censorship, was now disregarded; while the powers of the Inquisition and the range of its detailed supervision were widely extended.