Publication of the Index Librorum Prohibitorum

Timeline

1. 1555–1559Rome · ItalyAfter his election as pope in 1555, Paul IV pushed for stricter religious censorship, restoring and strengthening the Inquisition's powers and commissioning theologians to compile lists of heretical and reformist works. Before 1559 the papacy had issued several partial prohibitions, but lacked a unified, updatable authoritative index.
2. 1559Rome · RomeThe pope issued the first formal Index Librorum Prohibitorum by papal bull, banning numerous Reformation, humanist, and deemed immoral works classified by author and title, and stipulating that possessing, distributing, or printing prohibited books would be punished under canon law. The index's breadth and severity provoked backlash from some Catholic universities and the printing trade.
3. 1560–1564Rome · ItalyAfter Paul IV's death, Pius IV in 1564 issued a revised Index and the Index Librorum Prohibitorum Regulae on the basis of the Council of Trent's achievements, slightly relaxing some provisions and establishing a mechanism for regular updates; the 1559 edition thus became the starting point of the long-term institutionalization of papal book censorship.