“In order to put a stop to the circulation of pernicious opinions, and as far as practicable to bring certainty and protection to the faithful, it is our desire to bring the Index of prohibited books into a condition of completeness, so that Christians may be able to know what books it is safe for them to read and what they must avoid, and that there may be in this matter no occasion for doubt or question.... Therefore we give to you or to the majority of your body, full authority and powers to take action in regard to the examination and the classification of books, and to secure for aid in such work the service of learned men, ecclesiastics and laymen, who have knowledge of theology and of the canons; and to permit or to prohibit the use of books so examined, all authority given by my predecessors to their bodies or individuals for the carrying on of the work. It shall also be the duty of your body to elucidate or eliminate all difficulties or incongruities in the existing Indexes; to arrange for the correction or expurgation of all texts containing instructions of value, the service of which is marred by erroneous and pernicious material; to add to the Index the titles of all works found to be unworthy; and to prohibit the production and the use of all books so condemned; and to give permission for the reading of books approved and of books corrected and freed from error; and for the purpose of facilitating your task, you shall enjoin upon all bishops ... doctors, masters, printers, booksellers, magistrates, and others to coöperate with your body in carrying out the regulations formulated by your body for the supervision, control, and improvement of literature, and for the protection of the faithful against heresy.” In the Bull _Immensa_ of Sixtus V, January, 1587, the Congregation of the Index is directed to secure co-operation from the universities of Paris, Bologna, Salamanca, and Louvain, and other trustworthy institutions, in the work of examining and correcting books. (The selection of the universities recommended is interesting.) The Congregation is empowered to give permissions, exclusively for use in connection with the Index, to the scholars selected from these universities, and to other scholars whose service is utilised, to read the forbidden books without a special papal dispensation.