Nicolaus Copernicus was a Renaissance-era polymath who formulated a model of the universe that placed the Sun, rather than the Earth, at the center. His seminal work, 'De revolutionibus orbium coelestium' (On the Revolutions of the Heavenly Spheres), published just before his death in 1543, triggered the Copernican Revolution. This shift from a geocentric to a heliocentric model was a major turning point in the history of science, leading to the Scientific Revolution. Copernicus was a cautious man; he waited decades to publish his findings, partly due to the mathematical complexity of his model and partly out of fear of religious repercussions. While his model still incorrectly used circular orbits rather than elliptical ones, it correctly identified the Earth as just one of several planets orbiting a central star. His work paved the way for future astronomers like Kepler and Galileo to refine our understanding of the solar system.