#OTD in 1616.
Nicolaus Copernicus's book On the Revolutions of the Heavenly Spheres is added to the Index of Forbidden Books 73 years after it was first published. The book, first printed in 1543 in Nuremberg, Holy Roman Empire, offered an alternative model of the universe to Ptolemy's geocentric system, which had been widely accepted since ancient times.
https://en.wikipedia.org/wiki/De_revolutionibus_orbium_coelestium
About Copernicus at PG:
https://www.gutenberg.org/ebooks/search/?query=copernicus&submit_search=Search