This shipwreck, this holocaust of books will stop the production of them in your country also, if I do not err, and will teach editors to be upon their guard.

As you love me and yourself, sit and look at your bookcases without opening their doors, and beware lest the very cracks let emanations come to you from those forbidden fruits of learning.' This letter was written in 1559, when Paul proscribed sixty-one presses, and prohibited the perusal of any work that issued from them.

He afterwards withdrew this interdict.

But the Index did not stop its work of extirpation.
Another embarrassment which afflicted men of learning, was the danger of possessing books by heretics and the difficulty of procuring them.[130] Yet they could not carry on their Biblical studies without reference to such authors as, for example, Erasmus or Reuchlin.

The universities loudly demanded that books of sound erudition by heretics should at least be expurgated and republished.