Four centuries ago, on March 5, 1616 the Congregation of the Index "suspended" the publication of De Revolutionibus "until corrected". It took more than four years for that correction to be issued on May 15, 1620. Here it is in full. As you can see, it is by no means very aggressive: just a few tweaks here and there. One might as well wonder what was all the fuss about in the first place. (I shall share my suspicions with you on May 26.)
The Fathers of the Holy Congregation of the Index decreed that the writings of the distinguished astronomer Nicolaus Copernicus, On the Revolutions of the World, were to be absolutely prohibited, because he does not treat as hypotheses, but advances as completely true, principles about the location and the motion of the terrestrial globe that are repugnant to the true and Catholic interpretation of Holy Scripture; this is hardly to be tolerated in a Christian. Nevertheless, since Copernicus's work contains many things that are very useful generally, in that decision they were pleased by unanimous consent to allow it to be printed with certain corrections according to the emendation below in places where he discusses the location and motion of the earth not as a hypothesis but as an assertion. In fact, copies to be subsequently printed are permitted only with the above-mentioned places emended as follows and with this correction added to Copernicus's preface.
Emendation of the passages in Copernicus's book which are deemed suitable for correction:
In the preface, toward the end, delete everything from the beginning of the last paragraph up to the words "this work of mine," and substitute: "For the rest, this work of mine..."
In book 1, chapter 1, page 6, where it says "However, if we consider the matter more closely...", substitute: "However, if we consider the question more closely, we think it is immaterial whether the earth is placed at the center of the world or away from the center, so long as one saves the appearances of celestial motions."
In chapter 8 of the same book, this whole chapter could be expunged since it explicitly treats of the earth's motion while it refutes the ancient arguments proving its rest; however, since it is preferable to speak problematically, so as to satisfy scholars and to keep integral the book's sequential order, it may be emended as follows.
First, on page 6, delete the sentence from "Why therefore" to the words "We sail out," and correct the passage in this manner: "Why therefore can we not grant it the motion suitable to its shape, rather than rendering unstable the whole universe, whose limits are unknown and cannot be known, and why not grant that the things which appear in heaven happen in the same manner as expressed by Virgil's Aeneas?"
Second, on page 7, the sentence beginning with "I also add" should be corrected this way: "I also add that it is no more difficult to attribute motion to that which is in a place in a container, namely to the earth, than to the container."
Third, on the same page, at the end of the chapter, the passage from the words "You see" till the end of the chapter is to be deleted.
In chapter 9, page 7, correct the beginning of this chapter up to the sentence "For the fact that..." thus: "If, then, I assume that the earth moves, I think that we now have to see also whether several motions can belong to it. For the fact that..."
In chapter 10, page 9, correct the sentence beginning with "Consequently" thus: "Consequently we should not be ashamed to assume..." And a little below that, where it says "is correctly attributed to the motion of the Earth," substitute: "is consequently attributed to the motion of the Earth."
Page 10, at the end of the chapter, delete the very last words: "Such truly is the size of this structure of the Almighty's."
In chapter 11, the title of the chapter is to be changed in this manner: "On the Hypothesis of the Triple Motion of the Earth, and Its Demonstration."
In book 4, chapter 20, page 122, in the title of the chapter, delete the words "these three stars," since the earth is not a star, as Copernicus would have it.
Fra Franciscus Magdalenus Capiferreus, O.P., Secretary of the Holy Congregation of the Index.
Rome, Press of the Apostolic Palace, 1620
(Favaro XIX, pp. 400-401; tran. Finocchiaro, pp. 200-202)