Copernicus' work 'De revolutionibus orbium coelestium' (translated as 'On the Revolutions of the Heavenly Spheres') was first printed in 1543.
Copernicus' astronomical model (pictured) was the first to place the Sun at the center of the solar system, with the planets orbiting it. This model is now referred to as "Copernican heliocentrism"
While this is now common belief, at the time it was believed that Earth was at the center of the universe, and that the Sun, Moon, planets, and stars all orbiting around it.