On the Revolutions of the Heavenly Spheres by Nicolaus Copernicus
De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres), first printed in 1543 in Nuremberg, is the seminal work on the heliocentric theory of astronomer Nicolaus Copernicus (1473–1543). The book offered an alternative model of the universe to Ptolemy's geocentric system, which had been widely accepted since ancient times.