The _Magister_ of the papal palace (who was always a Dominican) was the standing counsel of the Inquisition and of the Congregation of the Index. The _Magister_ held at one time the office of papal chaplain, and later served as the personal adviser of the pope in theological matters. Leo X assigned to the _Magister_ (acting in conjunction with the cardinal vicar) the control of the censorship for Rome of books to be printed, and this function is still retained by him.[105] In 1600, Clement VIII decides (through Cardinal Baronius) that the Congregation has jurisdiction not only over books, but also over the authors, printers, and readers of the same; but that it must not interfere in the matters of heresy reserved for the control of the Inquisition.[106] Latinus (1593, later counsellor of the Congregation) relates that having occasion to read a volume by Paschasius, he had inadvertently proceeded with the reading of a treatise by Bertram which was bound in with this, forgetting that the latter was on the Index. On recognising his error, he threw away the book, and appealed to the Cardinal of Ermland, Grand Penitentiary, for absolution. His sin had brought him under the “reserved excommunication.” Later, the secretary of the Congregation had authority to give permission for the reading of prohibited books (with a few exceptions), but for no term longer than three years, and only in connection with an application on certificate from a bishop, vicar-general, or general of an order. The first _Magister_ of the palace was St. Dominic. The office was held more than once by cardinals. Since the beginning of the 17th century, the _Magister_ or his associate (_Socius_) is empowered, for the city of Rome, to prohibit the printing and the reading of books. Both officials have also the authority to permit the use of books other than the works of authors placed in Class I, or of books which treat of theological matters. For instance, in 1574, the _Magister_ Constabile gave permission to the scholar, Pierre Morin, to make use of the Greek lexicon of Stephanus (Estienne). Doctor Shahan (of the Catholic University of America) gives me the following statement concerning the organisation and the work of the Congregation: “The Congregation of the Index has, since its formal organisation, always had for its Secretary a member of the Dominican Order. The ‘Master of the Sacred Palace’ is also, _ex officio_, a member of the Congregation with the title of Perpetual Assistant. The usage under which the office of the Secretary and the office of Perpetual Assistant are always held by Dominicans is explained as follows: