First, let’s re-frame the question. It is obvious that the Church, as an institution, never sought to have Copernicus or anyone else killed. The question is, “Did certain Catholic churchmen seek to have Copernicus killed, perhaps believing that his murder would further the cause of Christianity?”
Those who assert that the second question is true are obliged to prove it. Politely insist that proof be furnished. From the known record of Copernicus’s life, we see that he probably suffered a stroke and perhaps some form of dementia in his last days, but there is no hint of foul play (cf. Nicolaus Copernicus from the Catholic Encyclopedia). Proving murder on the part of rogue ecclesiastics after five centuries is going to be a difficult task for a modern conspiracy theorist, particularly since Copernicus often worked in the service of the Church throughout his adult life and his last book Six Books on the Revolutions of the Celestial Orbits was dedicated to Pope Paul III.
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