Nicolaus Copernicus (February 19, 1473 - May 24, 1543) was the astronomer who formulated the first modern heliocentric theory of the solar system.
His epochal text, De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), is often conceived as the starting point of modern astronomy, as well as a central and defining epiphany in the history of all science.
Among the great polymaths of the Scientific Revolution, Copernicus was a mathematician, astronomer, jurist, physician, classical scholar, Catholic cleric, governor, administrator, diplomat, economist and soldier.
Amid these extensive responsibilities, astronomy served as no more than an avocation.
Nonetheless, his conception of the sun (rather than the Earth) at the center of the solar system is considered among the most important landmarks in the history of science.