Nicolaus Copernicus (Polish: Mikołaj Kopernik; German: Nikolaus Kopernikus; in his youth, Niclas Koppernigk;Italian: Nicolò Copernico; 19 February 1473 – 24 May 1543) is a Renaissance astronomer and the first person to formulate a comprehensive heliocentric cosmology, which displaces the Earth from the center of the universe.

Copernicus' epochal book, De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), published just before his death in 1543, is often regarded as the starting point of modern astronomy and the defining epiphany that began the scientific revolution.

His heliocentric model, with the Sun at the center of the universe, demonstrates that the observed motions of celestial objects can be explained without putting Earth at rest in the center of the universe.

His work stimulates further scientific investigations, becoming a landmark in the history of science that is often referred to as the Copernican Revolution.

Among the great polymaths of the Renaissance, Copernicus is a mathematician, astronomer, physician, quadrilingual polyglot, classical scholar, translator, artist, Catholic cleric, jurist, governor, military leader, diplomat and economist.

Among his many responsibilities, astronomy figures as little more than an avocation – yet it is in this field that he makes his mark upon the world.