The theory that the Sun is the center of the solar system, known as heliocentrism, was first proposed by the ancient Greek astronomer Aristarchus of Samos around the 3rd century BC.

However, it was Nicolaus Copernicus who, in the 16th century, published the influential book "De Revolutionibus Orbium Coelestium" (On the Revolutions of the Heavenly Spheres) that revived and expanded on the heliocentric model.

Copernicus' work provided a detailed mathematical framework for the heliocentric theory, and it is generally credited with being the major catalyst for the shift in scientific thinking from the geocentric (Earth-centered) model to the heliocentric model.