Copernicus was a Polish astronomer who lived from 1473 to 1543 AD.
How do we account for the fact that the Sun rises in the east and sets in the west? Surely that means the Sun moves around our Earth. Doesn't it? Aristotle said the Sun moved around the Earth. That settles it, then! Doesn't it?
What about the stars? And the planets? Oh, those planets -- even the word "planet" means "wanderer" and "untrustworthy".
Copernicus propsed a theory that the Sun was the center of "everything" and that our Earth -- and the planets -- moved in orbits around the Sun.
Boy! did that ever cause a stir!
For his own safety, Copernicus did not publish his theory until he was near death. His book De Revolutionibus was finally published on the day he died, May 24, 1543.