Copernicus' heliocentric system overthrew what was known as geocentrism the belief that everything in the universe revolved around the earth.

WSJ: Henninger: The Obamaian Universe

Clavius, a Jesuit who taught at the Collegio Romano in Rome, is often remembered as an early skeptic in the great battle over Copernicus and the heliocentric system.

FORBES: A Long Forgotten Father of the Scientific Revolution