This was confirmed and extended by the Bull Inter multipliées of Alexander VI in 1501. At the Fifth Lateran Leo X in 1515 authorised the Master of the Sacred Palace to act as censor in Rome and the papal States; and the Inquisition in 1543 began to regard the censorship as one of its functions. The first lists of prohibited books were however drawn up in 1546 and 1550 at Louvain, in 1549 at Cologne, and by the Sorbonne between 1544 and 1551. The first papal Index was that of Paul IV, which was published in 1559. It was arranged alphabetically but under each letter came three categories. The first class consisted of the heresiarchs, all of whose writings were prohibited. This was a mere list of names. The second class consisted of writers, some of whose productions, which were enumerated, tended to heresy, impiety, magic, or immorality. The third class consisted of writings, chiefly anonymous, which were unwholesome in doctrine. The Index of Paul IV met with much opposition; and Naples, Milan, Florence, and Venice refused to print or enforce it. Pius IV modified it in 1561 by allowing the use of non-Catholic editions of the Fathers and other inoffensive writings to licensed readers, provided comments by heretics of the first class had been previously erased. No Index Eacpurgatorius, however, as distinguished from an Index Librorum Prohlbitorum, was ever published officially at Rome. The harder work of pointing out particular passages which must be deleted was only undertaken in Spain. The Papacy contented itself with prohibiting books altogether or with a "donee corrigatur" of which nothing came.
The Index Librorum Prohlbitorum of Paul IV was however condemned at Trent as a bad piece of work; and a commission was appointed to revise it. Ten rules to be observed were drawn up, but the work itself was left to the Papacy. The new Index was published by the Papacy in March, 1564, and is known as the Tridentine Index. The Index of Paul IV was improved, and some of its worst blunders removed. It was accepted by Portugal, Belgium, Bavaria, and parts of Italy. In 1571 Pius V set up a special Congregation of the Index distinct from the Inquisition; and in 1588 this body was empowered by Sixtus V to undertake further revision of the Index. Twenty-two new rules took the place of the ten laid down at Trent; and this new Index was published in 1590. Shortly after its publication, however, Sixtus V died; and Clement VIII restored the Tridentine rules and issued another Index in 1596. The materials collected for the Index of 1590 were used, though the Spanish Index of Quiroga published in 1584 was one of the chief sources. The Index of 1596 remained the standard, though additions were made to it, until the middle of the eighteenth century.
So far as the southern nations were concerned the Index achieved its work. The peoples who continued to adhere to the Catholic Church were cut oft' from the culture and science of the North, and a serious blow was dealt to human progress. It was impossible for such measures
