During the sixteenth and seventeenth centuries, the Inquisition was the institution most invested in the censorship of printed books in the Portuguese empire. Besides publishing the Indices of Forbidden Books, the Holy Office was also responsible for overseeing their implementation and ensuring their efficacy in preventing the importation, reading, and circulation of banned books.

Considering the books and men of science condemned in the Indices of 1547, 1551, 1561, and 1581, I have shown that the most frequent subjects targeted by the Portuguese Inquisition were medicine, natural history, astronomy, judicial astrology, and divinatory arts.

By studying the traces of expurgation practices in the Portuguese National Library’s collections, I have also found that, with few exceptions, the expurgation of books of science were relatively mild and generally concerned the erasure of names of renowned Humanists, Protestants, Jews, and heterodox Catholics. Moreover, in contrast with the censorship of lascivious works, the expurgation of books of astrology does not seem to have been a priority for the Portuguese court until the seventeenth century.

This database will allow scholars and graduate students to research expurgation practices and mechanisms of censorship in a significant collection of forbidden books. In due course, collections from other libraries may be added.

Some of the results of the on-going investigation on the Portuguese Inquisition and the censorship of science books were published in 2020 (see Francisco Malta Romeiras, “Putting the Indices into Practice: Censoring Science in Early Modern Portugal,” Annals of Science 77 (2020): 71–95).

Francisco Malta Romeiras