The Ten Rules

Council of Trent (1545–1563).
Sacros. Concilium Tridentinum: Editio reformata . . . cum indice librorum prohibitorum ex praescripto Concilii.
Cologne: Johannes Busaeus, 1664. (AFH7502)

The Tridentine Index of 1564 presented ten rules that were established by the Council of Trent to control the censorship of texts. In the Index librorum prohibitorum that accompanies this 1664 edition of the Council’s decrees, the ten rules were reprinted in full. These are summarized in English below:

1. All books condemned by popes or councils before 1515 will remain prohibited.
2. All books by “heresiarchs” (heretical leaders) and theological books by heretics are prohibited.
3. Heretics’ Bible translations are banned; heretics’ translations of other texts require approval.
4. Vernacular translations of the Bible by Catholic scholars require approval.
5. Compilations of earlier works edited by heretics require correction and approval.
6. Theological writings in vernacular languages require correction and approval.
7. Obscene or immoral works are prohibited; Classical works may be read by adults.
8. Books that are generally sound, but which contain isolated heresies must be corrected.
9. All books treating magic, superstition, astrology, or occult practices are prohibited.
10. The bishop and the inquisitor require all books to be licensed prior to publication.

These rules were expanded and modified over the centuries, but they remained the core determinants for Catholic censorship until use of the Index librorum prohibitorum was discontinued in 1966.