Index Librorum Prohibitorum

Censored and banned literature: 1559-1948

The Index of Forbidden Books (Index Librorum Prohibitorum) was published on the authority of the Roman Catholic Church. It should be noted that the Index only contains books that ecclesiastical authority was asked to act upon. The lists had official sanction in all Catholic countries.

The Index of Forbidden Books


Index Librorum Prohibitorum (1559)Index Librorum Prohibitorum (1559)The 1948 edition of Index Librorum Prohibitorum is included in the "Beacon for Freedom of Expression" data base. The first edition of Index Librorum Prohibitorum was published in 1559, and subsequently published in 19 editions by different popes through the centuries. The last edition was published in 1948, only to be suppressed in 1966.

In addition to the Indexes, Expurgatory Catalogues were issued, containing lists of literary works not entirely forbidden, but where sentences or parts were censored. The Index and Expurgatory Catalogues did not represent the total legislation of the church regulating reading by Roman Catholics, or was it a complete catalogue of forbidden reading.

Grounds of censorship

The purpose of the "Index of Forbidden Books" was to prevent the contamination of the faith or the corruption of morals of Roman Catholics according to canon law, through the reading of theologically erroneous or immoral books.

Canon law, lasting in effect until 1966, prescribed two main types of censorship:

  1. Pre publication censorship of books by Roman Catholics in regard to matters of faith and morals
  2. The condemnation of published books, thus listed in the Index Librorum Prohibitorum.

Censoring body: Roman Catholic Church Authority (Sacred Congregation of the Roman Inquisition)


The censorship of books developed by the Roman Catholic Church remains an outstanding example in Christendom of long lasting and comprehensive religious censorship, at times ruthlessly acted upon by the Roman Inquisition.

In order to fend off a heretical threat to Christian doctrine, Creeds such as the Nicene Creed promulgated in AD 325, were devised. In ca. 496 AD Pope Gelasius I issued a decree containing lists of recommended as well as banned books, generally regarded as the first Roman Index. However, the church's concern for dangerous books is evident well before 496 AD.

The papacy of Pope Pius V (1566-72) is marked as one of the most austere periods in the history of the Roman Catholic Church. Known as a relentless persecutor of heretics, Pius also reformed the missal and breviary, although he left the medieval canon virtually unchanged, as it remained until 1970.

The first "Index of Forbidden Books", banned for their heretical or ideologically dangerous content, was drawn up by order of Pope Paul IV and published in 1559 by the Sacred Congregation of the Roman Inquisition. The Sacred Inquisition acting as the zealous guardians of the Faith executed their office with severity. Intellectuals were pursued vigorously for their acceptance of Protestant doctrines, or for heretic ideas. The most famous banned author is undoubtedly Galileo (1633). The objective of the lists was to protect the orthodoxy and ward of significant challenges to the teachings of the canonical texts. With the invention of the printing press in Europe in the middle of the 15th Century, the problem of control increased. As more books were written, copied and increasingly widely disseminated, subversive and heretical ideas were spread beyond control.

But also printers and booksellers faced the same dangers of persecution. In the late 16th century, a great number of Dutch printers chose to flee to Switzerland and Germany after a special Congregation of the Index was established.

The system of censorship created by the Catholic Church in Europe was also exported to the forcibly colonised countries in the Americas. When the Inquisition was established in Peru in 1569, the Tribunal's district ranged from Panama to Chile and Rio de la Plata.

In his article The Lima Inquisition and Book Censorship ("The Lima Inquisition and Book Censorship, 1570-1820" Study and Annotated Bibliography, by Pedro Guibovich, University of Columbia, USA 1999), the Peruvian historian Pedro Guibovich notes: "The Inquisition established in Peru in 1568, was part of a colonial policy by Philip II of Spain, designed to deal with the political and ideological crisis in the Peruvian viceroyalty. The Peruvian system was a blueprint of the Spanish, entailing control of the import of books, the inquisitorial officers periodically examining ships and luggage in ports, inspecting libraries, bookstores and printing houses. More detailed measures were implemented, such as (Carta acordada of 1605) ordering booksellers to present to officers of the Holy Office detailed inventories of their books."

Guibovich further notes: "Annual readings of the Edict of Faith were encouraged by the Tribunal as an exercise in denunciation of books. Threatened with excommunication, believers had to denounce those that: " have had and have books of the sect and opinions of the said Martin Luther and his followers or the Koran and other books of the sect of Mahomet (…) or any other books banned by the Holy Office of the Inquisition."

Excerpt translation from the Preface of Index Librorum Prohibitorum


Index of Prohibited Books

Year 1940

Note: The list now has status as a historic document.

"The Holy Church has through many centuries carried out immense persecutions, and the number of heroes who sealed the Christian faith with their blood, were multiplied. Today we face a struggle which is lead by the Devil himself; it is founded on something both insincere and destructive; Malicious publications.

No other danger is greater, it threatens the faith and exercise of custom and integrity, therefore the Holy Church will increasingly point this out to the Christians, in that way enabling them to retreat before this threat."

"The Holy Church, which was appointed by God himself, could not proceed otherwise. It represents an infallible master who securely leads his believers. Thus, the Church is equipped with all necessary and useful means to prevent the infection of the herd of Jesus, by the erroneous and corrupt which will show itself irrespective of the mask it hides behind. Consequently The Holy Church has the duty, and hence the right, to pursue this aim.

One must not claim that the condemnation of harmful books is a violation of freedom or a war against the Light of Truth, and that the index of forbidden books is a permanent attack against the progress of science and literature."

"Irreligious and immoral books are written in a seductive manner, often with themes which deal with fleshly passion, or themes that deceive the pride of the soul. These books are carefully written to make an impression and aim at gaining ground in both the heart and mind of the incautious reader."

"In addition, the necessity to suppress malicious publications for the wellbeing of the public, has particularly been proven lately, when even civil governments, have used preventive censorship to protect the judicial system and public order, with a rigidity unknown to the Church. This shows us how well it corresponds with the true liberty.

No matter how much true literary and scientific values a book can possess, it cannot legitimate the distribution which opposes the religion and good custom. On the contrary, the more subtle and seductive the evil is, the more it necessitates stronger and more efficient suppression of it."

"These prohibited books were written to make an impression, and all this have been exposed to remove any doubt occurring among the Catholic believers. This explanation is intended for the devoted, good sons, who readily listen to the words of the good Shepherd Jesus, and to his representative on earth; the Pope. In short, this is intended for those who scrupulously comply with the rules, possibly with some exceptions arising from extreme conditions, where the Church grant exemptions for those who dissociate themselves from reading or owning the books which have been prohibited by the Holy Church."

* From Palazzo del S. Uffizio,

Festa del S. Cuore di Gesu

7th of June 1929


Suprema S. C. Del Sant'Uffizio Secretary

Unauthorised translation by Betty Cutolo


The 1948 edition of the Index of Forbidden Books

List of Indexes in the Beacon for Freedom of Expression data base

Publications in English relevant to the censorship of the Catholic Church