Index Librorum Prohibitorum
“Index of forbidden books.”
Catholic Church, 1559–1966
What does “Index Librorum Prohibitorum” mean?
Index Librorum Prohibitorum translates as “Index of forbidden books.”
The official list of books Catholics were once forbidden to read; today a byword for censorship.
“Index Librorum Prohibitorum” word by word
| Latin | English | Grammar |
|---|---|---|
| Index | list, register | nominative singular masculine of index, indicis, “pointer, list”; the subject of the phrase |
| Librorum | of the books | genitive plural of liber, libri, “book” (second declension masculine); tells you whose or what kind of list |
| Prohibitorum | of the forbidden ones | genitive plural of the perfect passive participle prohibitus, from prohibeo, “to forbid”; agrees with librorum, so “of forbidden books” |
How to pronounce “Index Librorum Prohibitorum”
The main difference is in the vowels: Classical gives i a short “ih” sound and c/g hard, while the Church version softens them (the i in index becomes “ee”). Stress falls on the second-to-last syllable of librorum and prohibitorum.
The story behind it
Word for word the title means “list of forbidden books”. It is the official name of the catalogue of publications that the Catholic Church barred its members from reading without permission.
The first Index was issued under Pope Paul IV in 1559, during the Counter-Reformation, when the Church was trying to limit the spread of Protestant and other works it judged dangerous to faith or morals. It was revised and reissued many times over the following four centuries.
The Index was abolished in 1966. Since then the phrase has lived on as shorthand for institutional censorship, and it is often used in discussions of banned books and intellectual freedom.
How to use “Index Librorum Prohibitorum”
It suits a caption for a post about banned books, a gift for a bookish friend, a title for a library or reading-list project, or a dry joke on a bookshelf or tote bag. As a tattoo it reads as a statement about reading, censorship and freedom of thought.
- Latin
- Index Librorum Prohibitorum
- English
- Index of forbidden books.
- Source
- Catholic Church, 1559–1966
- Era
- Renaissance
- Theme
- History
Common mistakes
- It is not a list of books banned by the state or by a university. It was specifically a Church catalogue for Catholics.
- Prohibitorum is genitive plural and must agree with librorum. Changing one without the other, for example to “prohibitus”, makes the Latin wrong.
- The Index did not end in 1559. That was the first edition; it kept being updated until it was abolished in 1966.
- It is often written in English as just “the Index”, which can be confused with other kinds of index, such as a book index or a stock index.
Questions about “Index Librorum Prohibitorum”
What does “Index Librorum Prohibitorum” mean literally?
“List of forbidden books”. Index means list, librorum is “of the books” and prohibitorum is “of the forbidden ones”.
When was the “Index Librorum Prohibitorum” created and abolished?
The Catholic Church first issued it in 1559 under Pope Paul IV and abolished it in 1966, after about four centuries of updates.
How do you pronounce “Index Librorum Prohibitorum”?
In Classical Latin: IN-deks lih-BROH-room proh-hih-bih-TOH-room. In Church Latin: EEN-deks lee-BROH-room proh-ee-bee-TOH-room.
Is “Index Librorum Prohibitorum” correct Latin for a tattoo?
Yes. It is a genuine historical title and the grammar is sound, with prohibitorum agreeing with librorum in the genitive plural.
More to explore
Translation and grammar checked by Latin Quoter · last reviewed November 2026
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