Index Librorum Prohibitorum · first issued in 1559 · the Reformers condemned in all their works · set aside as church law in 1966.

The Index was Rome’s official catalog of forbidden books. A Catholic could not read, keep, print, or sell a listed work without permission, under pain of excommunication. An entry might condemn an author’s entire output, a single title, or a book only “until corrected” (donec corrigatur).

Its Beginning

The printing press carried the Reformation faster than any bishop could answer it. The Fifth Lateran Council had already required church approval before any book was printed (1515), and the theologians of Paris and Louvain drew up lists of condemned books in the 1540s. In 1559 Paul IV issued the first Roman Index through the Inquisition. The Council of Trent then appointed fathers to revise it, and Pius IV published their work with ten governing rules on March 24, 1564. From 1571 a standing Congregation of the Index kept the list current. The last edition appeared in 1948.

A Sampling

The second of Trent’s rules struck at the Reformers by name:

The books of arch-heretics … such as Luther, Zuinglius, Calvin, Balthazar, Pacimontanus, Swenchfeldius, and such like, of what name, title, or argument soever, are utterly prohibited.

Rules of the Index, Rule II (1564)

The fourth rule allowed Bibles in the common tongue only by permission of a bishop or inquisitor, and denied absolution to anyone who read one without it until he surrendered the book. Later editions added such works as Copernicus’s On the Revolutions (1616), Pascal’s Provincial Letters (1657), Descartes’s philosophical works (1663), Locke’s Essay Concerning Human Understanding (1734), and Kant’s Critique of Pure Reason (1827). A digitized copy of the 1564 Index, printed by Paolo Manuzio, is held by the Biblioteca Nazionale Centrale of Florence.

Rome’s Position Today

On June 14, 1966, the Congregation for the Doctrine of the Faith declared that the Index “no longer has the force of ecclesiastical law with the attached censure,” yet “remains morally binding” (Notification). A decree of November 15, 1966, abrogated the canons behind it while reminding the faithful of “the value of the moral law which absolutely prohibits endangering faith and good morals” (Decree). The list is gone, but the claim behind it remains. The present Code of Canon Law gives the pastors of the Church “the duty and right to condemn writings which harm correct faith or good morals,” and still requires church approval for every translation of Scripture (canons 823, 825).

The Bereans were commended not for avoiding what they read, but for searching the Scriptures daily to test it (Acts 17:11).

Roman Catholicism