Although Charles V. and Philip II. neglected nothing that could prevent the introduction of prohibited books into Spain, several which were favourable to the Lutheran heresy penetrated into the kingdom. In 1558 the inquisitor-general published an edict more severe than any of the preceding; and also drew up an instruction for the use of the inquisitors; importing, that all books mentioned in the printed catalogue should be seized; that a public _auto-da-fé_ should be made of those tending to heresy; that the commentaries and notes attributed to Melancthon should be suppressed in all the treatises on grammar where they were introduced; that the bibles marked as being suspected should be examined; that no books should be seized except those mentioned in the list; that all the books printed in Germany since 1519 without the name of the author should be examined; that the translation of _Theophylact_ by _OEcolampadius_ should be seized; likewise some volumes of the works of St. John Chrysostom, which had been translated by that arch-heretic and _Wolfang Nusculus_; that the commentaries by heretics on works composed by catholics should be suppressed; and that a book on medicine might be seized, although it was not mentioned in the index. When this edict was published, Francis Sanchez, professor of theology in the university of Salamanca, wrote to inform the Supreme Council, that he had occupied himself for several years in examining dangerous books, and gave his opinion on the course which ought to be pursued. The council, in consequence, decreed that those theologians in the university who had studied the Oriental languages, should be obliged, as well as other persons, to give up their Hebrew and Greek Bibles to the commissaries of the holy office, on pain of excommunication; that the proprietors of Greek, Arabic, and Hebrew books, not mentioned in the list, should not be molested; that the order concerning the books printed without the name of the author, related only to modern productions; that the request made by some persons to be allowed to keep _Pomponius Mela_, with the commentary of _Nadicano_, should be refused; that these books should be remitted to the council to be examined; that the order to seize all works containing errors should only be applied to modern books; and that the _Summa Armata_ of Durand, of Cajetan, Peter Lombard, Origen, Theophylact, Tertullian, Lactantius, Lucian, Aristotle, Plato, Seneca, and other authors of that class, should be allowed to circulate; that the council, being informed that several catalogues of prohibited books existed, would unite them, and compose one general catalogue.