---
title: The Index of Prohibited Books (1559-1966)
url: https://propagandaarchive.org/case-studies/index-librorum-prohibitorum/
description: from 1559 to 1966 the Catholic Church published a list of books its members were forbidden to print, sell, own or read without permission, backed by…
section: Case studies
---

![Illustration: a pre-1914 imperial intelligence-dossier collage of colonial telegraph logs, sepia field photography and empire maps.](https://propagandaarchive.org/static/generated/detail/hero-pre1914.jpg)

[Case studies](https://propagandaarchive.org/case-studies/)

# The Index of Prohibited Books (1559-1966)

At a glance

From 1559 to 1966 the Catholic Church published a list of books its members were forbidden to print, sell, own or read without permission, backed by prior review of new books (the imprimatur)…

- **When:** 1559
- **Actor:** Catholic Church: the Roman Inquisition…
- **Target:** Catholic readers, printers, booksellers and authors…
- **Confidence:** **high** Multiple independent open sources, low disagreement about the facts
- **Techniques:** [Name-calling](https://propagandaarchive.org/techniques/name-calling/) [Card stacking](https://propagandaarchive.org/techniques/card-stacking/)

Full details

- **Actor:** Catholic Church: the Roman Inquisition (Holy Office) under Paul IV, the Council of Trent and Pius IV, the Congregation of the Index (1571-1917), then the Holy Office and the Congregation for the Doctrine of the Faith
- **Target:** Catholic readers, printers, booksellers and authors; secondarily, printers and readers in states that enforced the Index

On this page

- [What happened](https://propagandaarchive.org/case-studies/index-librorum-prohibitorum/#what-happened)
- [How it works](https://propagandaarchive.org/case-studies/index-librorum-prohibitorum/#how-it-works)
- [Then and now](https://propagandaarchive.org/case-studies/index-librorum-prohibitorum/#then-and-now)
- [Positions on the record](https://propagandaarchive.org/case-studies/index-librorum-prohibitorum/#positions-on-the-record)
- [Same-method test](https://propagandaarchive.org/case-studies/index-librorum-prohibitorum/#same-method-test)
- [How to spot it](https://propagandaarchive.org/case-studies/index-librorum-prohibitorum/#how-to-spot-it)
- [Images](https://propagandaarchive.org/case-studies/index-librorum-prohibitorum/#images)
- [Sources](https://propagandaarchive.org/case-studies/index-librorum-prohibitorum/#sources)

On this page

**In one line:** from 1559 to 1966 the Catholic Church published a list of books its members were forbidden to print, sell, own or read without permission, backed by prior review of new books (the imprimatur), and in the same centuries Protestant and secular governments ran their own licensing and book-burning systems on narrower territory.

![Diagram: prior review before printing, the 1559 and 1564 lists with their rules, decrees of the Congregation of the Index such as the 1616 suspension of Copernicus "until corrected", the 1620 corrected text, and the end of the Index's legal force in 1966; English licensing and the 1553 burning of Servetus's book run alongside](https://propagandaarchive.org/case-studies/images/index-librorum-prohibitorum-diagram.svg)

![Title page of the Index librorum prohibitorum with the rules drawn up by the Fathers chosen by the Council of Trent, approved by Pius IV, Venice edition](https://propagandaarchive.org/case-studies/images/index-librorum-prohibitorum-1564-venice.jpg)

*Title page of the Tridentine Index, "with the rules drawn up by the Fathers chosen by the Synod of Trent", approved by Pius IV; Venice edition of 1564. Public domain (published 1564).*

## What happened

**Before the list: review before printing**

- **4 May 1515.** At its tenth session the Fifth Lateran Council approves the bull *Inter sollicitudines* of Leo X. No book may be printed without examination and written permission from the local bishop and the inquisitor; unauthorised printing carries burning of the books, fines, suspension from the trade and excommunication. This written permission is the origin of the imprimatur ("let it be printed").
- **1544 to 1559.** Other Catholic authorities publish lists first, among them the Paris Faculty of Theology (from 1544) and the Spanish Inquisition (1551, 1554, 1559).

![Title page of the Spanish Inquisition's 1559 catalogue of prohibited books issued by Fernando de Valdés, Valladolid](https://propagandaarchive.org/case-studies/images/index-librorum-prohibitorum-valdes-1559.jpg)

*The Spanish Inquisition's own 1559 list, the* Cathalogus librorum qui prohibentur*, issued by Inquisitor General Fernando de Valdés and printed in Valladolid (Pinciae) by Sebastián Martínez. This is not the Roman Pauline Index, which was published the same year. Public domain (published 1559); image from the University of Notre Dame's Inquisition collection via Wikimedia Commons.*

**The Roman lists**

- **1559, the Pauline Index.** The Roman Inquisition prepares and Paul IV issues the first Roman *Index auctorum et librorum*, printed in Rome by Antonio Blado. It has three classes: authors all of whose works are banned, individual named books, and anonymous books. The first class includes all of Erasmus's works.
- **24 March 1564, the Tridentine Index.** The Council of Trent leaves the finished list to the Pope; Pius IV promulgates it with the bull *Dominici gregis custodiae* and ten general rules. It bans a handful of Erasmus's works, including *The Praise of Folly* and the *Colloquies*, and allows the rest in expurgated editions.
- **The ten rules** (H. J. Schroeder's translation). Rule II bans the books of "heresiarchs" such as Luther, Zwingli and Calvin. Rule IV allows vernacular Bibles only by written permission, for readers who will draw from them "an increase of faith and piety". Rule VII bans books on things "lascivious or obscene", since "not only the matter of faith but also that of morals" is easily corrupted by them, while permitting ancient pagan authors "because of the elegance and propriety of the language". Rule VIII allows expurgated reissues; Rule X restates review before printing.
- **1571.** Pius V sets up the Congregation of the Index as a standing body of cardinals to keep the list (some scholarship dates its formal founding to 1572). The Holy Office, founded in 1542, also issues prohibitions.

**Notable entries**

- **5 March 1616.** A decree of the Congregation of the Index suspends Copernicus's *De revolutionibus* (1543) and Diego de Zúñiga's commentary on Job *donec corrigantur* ("until they are corrected"), bans Paolo Antonio Foscarini's letter outright, and bans all other books teaching the same thing. It calls the doctrine that the Earth moves and the Sun stands still "that false Pythagorean doctrine, altogether contrary to the divine Scripture" (*falsam illam doctrinam Pythagoricam, divinaeque Scripturae omnino adversantem*).
- **1620.** The Congregation publishes the corrections: about ten passages where Copernicus presents the Earth's motion as fact are struck out or reworded to read as hypothesis. Corrected copies could carry the note that the book was "corrected according to the Roman decree of 1620 and therefore permitted".
- **22 June 1633.** The Holy Office's sentence against Galileo orders "that the book Dialogue of Galileo Galilei be prohibited by public edict". The *Dialogue* had been printed in Florence in 1632 "Con licenza de' Superiori". It stays on the Index until the 1835 edition.
- **1663.** Descartes's *Meditations*, *Passions of the Soul* and *Opera philosophica* are listed *donec corrigantur*.
- **11 June 1827.** Kant's *Critique of Pure Reason* is placed on the Index.
- **1834 and 1864.** Victor Hugo's *Notre-Dame de Paris* is listed in 1834 and *Les Misérables* in 1864.
- **20 June 1864.** A decree of the Congregation lists Flaubert's *Madame Bovary* and *Salammbô*, seven years after a French court acquitted Flaubert over *Madame Bovary*.
- **25 January 1897.** Leo XIII's constitution *Officiorum ac munerum* rewrites the rules.
- **25 March 1917.** Benedict XV's motu proprio *Alloquentes proxime* abolishes the Congregation of the Index and returns its work to the Holy Office.
- **1948.** The 32nd and last edition appears under Pius XII, with about 4,000 titles. In 1948 the Holy Office also lists the complete works (*opera omnia*) of Jean-Paul Sartre; André Gide's complete works are added in 1952, after the last edition.

**The end**

- **8 November 1963.** At the Second Vatican Council, Cardinal Josef Frings of Cologne says the Holy Office's procedures are "a source of harm to the faithful and of scandal to those outside the Church"; its secretary, Cardinal Alfredo Ottaviani, replies that the remarks come from ignorance.
- **7 December 1965.** Paul VI renames and reorganises the Holy Office as the Congregation for the Doctrine of the Faith (CDF).
- **14 June 1966.** A CDF notification states that the Index no longer has the force of church law with penalties attached, but "remains morally binding": it still warns Catholics' consciences against writings that can endanger "faith and morals" (*Acta Apostolicae Sedis* 58, 1966).
- **15 November 1966.** A CDF decree, approved by Paul VI on 14 October, declares canons 1399 (books forbidden by law) and 2318 (penalties) of the 1917 Code of Canon Law no longer in force, effective 29 March 1967.
- **After 1966.** Prior review survives in narrower form: the 1983 Code of Canon Law still asks for a bishop's approval of certain religious books, such as Bible translations, catechisms and school religion texts.

**The record opened**

- **1984 to 2002.** J. M. de Bujanda's team at the Université de Sherbrooke publishes the eleven volumes of *Index des livres interdits* (with Droz, Geneva), editing the 16th-century indexes and, in volume XI, cataloguing the Roman Index from 1600 to 1966.
- **22 January 1998.** On a proposal of John Paul II, Cardinal Joseph Ratzinger, prefect of the CDF, opens the archives of the Holy Office and the Congregation of the Index to scholars, up to the death of Leo XIII (1903). Hubert Wolf of the University of Münster, who led research in them, publishes *Index: Der Vatikan und die verbotenen Bücher* in 2006.

## How it works

Censorship is not itself a technique id in FRAME's taxonomy; the tags below describe the official texts that announced, labelled and corrected the banned books.

- [Name-calling](https://propagandaarchive.org/techniques/name-calling/): the Index's own texts attach labels that stand in for the reader's own examination, because the reader is forbidden to examine the book. Rule II files authors under "heresiarchs". The 1616 decree describes heliocentrism as "that false Pythagorean doctrine, altogether contrary to the divine Scripture". A Catholic who obeyed the decree met the label, not the argument.
- [Card stacking](https://propagandaarchive.org/techniques/card-stacking/): the correction system published approved versions of banned books with passages removed. The 1620 corrections to Copernicus struck or reworded about ten passages, so that the permitted text could be read only as a hypothesis, and the corrected copy carried a note saying it was now permitted. Expurgated editions of Erasmus worked the same way. The reader got the author's name and most of the text, with the selection made by the censor.

The system had three parts: review before printing (the imprimatur, Rule X), a published list for books in circulation, and correction between ban and permission. The *Dialogue* passed the first in 1632 and was condemned in 1633.

## Then and now

![Frontispiece by Stefano della Bella and title page of Galileo's Dialogo, Florence 1632, with the line "Con licenza de' Superiori"](https://propagandaarchive.org/case-studies/images/index-librorum-prohibitorum-galileo-dialogo-1632.png)

*Frontispiece (Stefano della Bella) and title page of Galileo's* Dialogo*, printed in Florence by Giovanni Battista Landini, 1632. The foot of the title page reads "Con licenza de' Superiori" (with the permission of the superiors). Public domain (published 1632).*

A present-day authority that publishes a list of prohibited works is Russia's Federal List of Extremist Materials. Article 13 of Federal Law No. 114-FZ of 25 July 2002, "On Countering Extremist Activity", assigns the Ministry of Justice to keep, publish and post the list. It began in 2007 with 79 items and held 5,334 by 16 January 2023, sixteen years later. Each entry follows a final court judgment; entries include Russian translations of the Turkish theologian Said Nursi and Jehovah's Witnesses publications. The SOVA Center, a Moscow research group, calls the list's quality so poor that it cannot simply be used.

The differences are as plain as the likeness:

- **Who is bound.** The Index bound Catholics under church law, with penalties such as excommunication; states enforced it only where they chose to. The Russian list is state law for everyone in Russia, enforced by police and courts.
- **Who decides.** Index entries came from decrees of congregations of cardinals; Russian entries come from court judgments.
- **Scale and grounds.** The Index ended with about 4,000 titles after four centuries, on grounds of faith and morals. The Russian list passed 5,000 items in sixteen years, on grounds of extremism.

The sibling case [Apartheid South Africa's banned organisations, persons and publications](https://propagandaarchive.org/case-studies/apartheid-publication-bans/) covers another government that published lists of banned titles.

## Positions on the record

- **The Church's stated rationale.** In its own texts, the Index protects the faith and morals of the faithful. Leo XIII's *Officiorum ac munerum* (1897) calls watching over "the integrity of Christian faith and morals" the Pope's chief duty and says the Church has always tried "to restrain men from the reading of bad books, as from a deadly poison". Rule VII of 1564 gives the same reason for banning lascivious books. The 1966 notification keeps that rationale while dropping the penalties: the list "remains morally binding" as a warning to conscience.
- **Critics.** John Milton's *Areopagitica* (1644), addressed to an English Parliament that had just restored licensing, says "the Council of Trent and the Spanish Inquisition engendering together brought forth, or perfected, those Catalogues and expurging Indexes" that "rake through the entrails of many an old good author". Inside the Church, Cardinal Frings made the 1963 criticism quoted above.
- **Modern scholarship.** De Bujanda's volumes and the post-1998 archive work (Wolf and others) document the procedure from inside: how books came to the Congregation's attention, who the censors were, and what they reported.
- **This archive's reading.** The decrees, rules, editions and the 1966 notification are documented. How far the Index actually changed what Catholics read is not settled by the record: enforcement depended on bishops, inquisitors and states. The page does not rule on whether any listed book was right or wrong about faith, morals or astronomy.

## Same-method test

The same standard applies to Protestant and secular governments of the same era, and they did the same kinds of thing on smaller territory:

- **England.** Parliament's Licensing Order of 14 June 1643 restored review before printing. Milton's *Areopagitica* answered it on 23 November 1644 and was itself printed without a licence (image below). It also excludes Catholicism from the toleration it asks for ("I mean not tolerated Popery, and open superstition"), and from 1649 Milton served the Commonwealth as censor of the newspaper *Mercurius Politicus*. After the Restoration, the Licensing of the Press Act 1662 (14 Cha. 2 c. 33), "An Act for preventing the frequent Abuses in printing seditious treasonable and unlicensed Books and Pamphlets", required books to be licensed by different authorities depending on subject, with divinity going to the Archbishop of Canterbury or the Bishop of London. Parliament let it lapse in 1695.
- **Vienne and Geneva, 1553.** Michael Servetus's anti-Trinitarian *Christianismi restitutio* was printed in secret in 1553. The Catholic inquisition at Vienne, in France, convicted him on 17 June 1553 after he escaped, and burned him in effigy together with his books. The Protestant city of Geneva, where he was recognised in August, tried him and burned him alive on 27 October 1553 at Champel, with copies of the book. Three copies are known to survive (Vienna, Paris and Edinburgh).

The name-calling test applies to all three: the English Act's "seditious treasonable" and the Index's "heresiarchs" do the same work. The difference is scale and reach. The Roman Index claimed authority over every Catholic in every country for four centuries. England's licensing covered one kingdom, and the 1662 Act lapsed after 33 years. Geneva's jurisdiction was one city. In 1553 a Catholic and a Protestant authority each burned the same book.

![Title page of Areopagitica, 1644, author's presentation copy](https://propagandaarchive.org/case-studies/images/index-librorum-prohibitorum-areopagitica-1644.png)

*Title page of Milton's* Areopagitica: A Speech for the Liberty of Unlicenc'd Printing, to the Parlament of England *(London, 1644), author's presentation copy with the handwritten date "Novemb. 24". Public domain (published 1644; photograph facsimile published 1917).*

## How to spot it

- Look for a list that stands in for the reader's own judgment. The label tells the reader what the book is, and the rule says the reader may not check.
- Look for "corrected" or "expurgated" editions of a banned text. Ask what was cut, who cut it, and whether the edition says so.
- A permission line ("Con licenza de' Superiori", an imprimatur) records that a censor read the book before printing.
- Check the removal date as well as the entry: Galileo's *Dialogue* stayed listed until 1835.

## Images

| Image | Source | Licence |
| --- | --- | --- |
| Mechanism diagram (above) | Drawn for FRAME from this page's sourced facts (`make_diagrams.py`) | CC BY 4.0, FRAME |
| Title page of the Tridentine Index, Venice, 1564 | [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Index_Librorum_Prohibitorum_1.jpg) | Public domain (published 1564) |
| Galileo, *Dialogo*, frontispiece and title page, Florence, 1632 | [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Galileos_Dialogue_Title_Page.png) | Public domain (published 1632) |
| Milton, *Areopagitica*, title page, London, 1644 | [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Title_page_of_Areopagitica.png) | Public domain (published 1644) |
| Spanish Inquisition's *Cathalogus librorum qui prohibentur*, Valladolid, 1559 | [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Cathalogus_librorum_qui_prohibentur.jpg), from the University of Notre Dame | Public domain (published 1559) |

### Image gaps

- **The title page of the Roman Pauline Index of 1559 (Blado, Rome).** The only photographs found on Commons, of the copy in the Biblioteca Nazionale Centrale di Firenze, carry an Italian cultural-heritage restriction (ita-mibac) on reuse, so they are not used. The Spanish 1559 list above is shown instead and captioned as a different list.
- **The 1616 decree against Copernicus and a corrected copy of *De revolutionibus*.** No openly licensed image of the printed decree or of a censored copy was found in the time available. Library photographs of censored copies exist (for example in Poznań), but their licences were not checked.
- **A page of the 1948 edition.** Published after 1930, so its U.S. public-domain status is unclear.
- **The 1966 notification as printed in *Acta Apostolicae Sedis*.** vatican.va could not be reached from the build environment.

## Sources

**Church documents**

- Fifth Lateran Council, bull *Inter sollicitudines*, 4 May 1515; discussed in Nelson H. Minnich, ["The Fifth Lateran Council and Preventive Censorship of Printed Books"](https://www.taylorfrancis.com/chapters/edit/10.4324/9781315240336-7/fifth-lateran-council-preventive-censorship-printed-books-nelson-minnich).
- Pius IV, bull *Dominici gregis custodiae*, 24 March 1564, and the ten Tridentine rules; English in H. J. Schroeder, *Canons and Decrees of the Council of Trent*, reproduced by [EWTN, "Ten Rules Concerning Prohibited Books"](https://www.ewtn.com/catholicism/library/ten-rules-concerning-prohibited-books-1500).
- Congregation of the Index, decree of 5 March 1616, Latin and English at [Inters.org](https://inters.org/decree-against-copernicanism-1616).
- Holy Office, sentence against Galileo, 22 June 1633: [Museo Galileo](https://catalogue.museogalileo.it/indepth/SentenceCondemnationGalileo.html).
- Leo XIII, [*Officiorum ac munerum*, 25 January 1897](https://www.vatican.va/content/leo-xiii/en/apost_constitutions/documents/hf_l-xiii_apc_18970125_officiorum-ac-munerum.html).
- Benedict XV, motu proprio *Alloquentes proxime*, 25 March 1917; [Dicastery for the Doctrine of the Faith, "History"](https://www.doctrinafidei.va/en/profilo/storia.html).
- Congregation for the Doctrine of the Faith, [Notification regarding the abolition of the Index of books, 14 June 1966](https://www.vatican.va/roman_curia/congregations/cfaith/documents/rc_con_cfaith_doc_19660614_de-indicis-libr-prohib_en.html).
- Congregation for the Doctrine of the Faith, [Decree regarding canons 1399 and 2318 no longer in force, 15 November 1966](https://www.vatican.va/roman_curia/congregations/cfaith/documents/rc_con_cfaith_doc_19661115_decretum_en.html).

**Scholarship and reporting**

- J. M. de Bujanda (dir.), *Index des livres interdits*, 11 vols. (Sherbrooke: Centre d'études de la Renaissance; Geneva: Droz, 1984-2002); [vol. XI at Droz](https://www.droz.org/france/product/9782600008181).
- Hubert Wolf, *Index: Der Vatikan und die verbotenen Bücher* (Munich: C. H. Beck, 2006).
- ["Vatican opening Inquisition archives"](https://www.deseret.com/1998/1/24/19359586/vatican-opening-inquisition-archives/), Deseret News, 24 January 1998; [American Historical Association, "Palazzo del Sant'Uffizio"](https://www.historians.org/perspectives-article/palazzo-del-santuffizio-the-opening-of-the-roman-inquisitions-central-archive-may-1999/).
- [Internet Encyclopedia of Philosophy, "Erasmus, Desiderius"](https://iep.utm.edu/erasmus/) (Erasmus in the 1559 and 1564 indexes).
- [Centre Gustave Flaubert, "La mise à l'Index de Madame Bovary, le 20 juin 1864"](https://flaubert.univ-rouen.fr/labo-flaubert/archives-de-la-revue-flaubert/revue-flaubert-n8-2008/la-mise-a-lindex-de-madame-bovary-le-20-juin-1864/).
- [Commonweal, "A Dark Chapter"](https://www.commonwealmagazine.org/dark-chapter) (Kant, 1827).
- [Cambridge, Whipple Museum, "Starry Messenger: Copernicus's Book"](https://www.sites.hps.cam.ac.uk/starry/coperbooks.html) (the 1620 corrections).
- Cardinal Frings's intervention of 8 November 1963 and Ottaviani's reply: [Josef Frings](https://en.wikipedia.org/wiki/Josef_Frings), drawing on Yves Congar's council journal.

**Parallel censorship**

- John Milton, *Areopagitica* (1644), text at the [Milton Reading Room, Dartmouth](https://milton.host.dartmouth.edu/reading_room/areopagitica/text.shtml); [History of Parliament, "On this Day: 23 November 1644"](https://www.historyofparliamentonline.org/periods/stuarts/day-23-november-1644-publication-miltons-areopagitica-and-regulation-press); [First Amendment Encyclopedia, "John Milton"](https://www.mtsu.edu/first-amendment/article/1259/john-milton) (Milton as censor of *Mercurius Politicus*).
- Licensing of the Press Act 1662 (14 Cha. 2 c. 33): [Primary Sources on Copyright, "Licensing Act, London (1662)"](https://copyrighthistory.org/cam/tools/request/showRecord.php?id=record_uk_1662).
- Michael Servetus and *Christianismi restitutio*: [University of Edinburgh, Cultural Heritage Digitisation Service](https://libraryblogs.is.ed.ac.uk/diu/2018/03/30/michael-servetus-christianismi-restitutio/); [History of Information, "Michael Servetus"](https://www.historyofinformation.com/detail.php?id=1466).
- Russian Federation, Federal Law No. 114-FZ of 25 July 2002, "On Countering Extremist Activity", art. 13; [Ministry of Justice, Federal list of extremist materials](https://minjust.ru/en/node/221412); SOVA Center annual reports on xenophobia.