High Quality Content by WIKIPEDIA articles! The Index Librorum Prohibitorum (English: List of Prohibited Books) was a list of publications prohibited by the Catholic Church. A first version (the Pauline Index) was promulgated by Pope Paul IV in 1559, and a revised and somewhat relaxed form (the Tridentine Index) was authorized at the Council of Trent. The promulgation of the Index marked the "turning-point in the freedom of enquiry" in the Catholic world. The final (20th) edition appeared in 1948, and it was formally abolished on 14 June 1966 by Pope Paul VI.