Nicolaus Copernicus lived in Italy from 1473 to 1543, and published his comprehensive book on heliocentric theory the year he died. De Revolutionibus Orbium Colelestium (On the Revolutions of the Celestial Spheres) was the culmination of his study of the planetary movements. He determined that the planets were orbiting the Sun, not the Earth. He also concluded that direct or retrograde movement of planets was an illusion from the perspective of a moving Earth, not from their own motion, as previously thought. His theories kicked of their own revolution, and are considered a milestone in science.
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