The ancient Greek astronomer and mathematician known as Aristarchus of Samos was the first person to propose a heliocentric view of the solar system. He lived circa 310 B.C. to 230 B.C. and stated that the Earth, like other planets, orbited the sun, which he regarded as the universe's center.
Copernicus, in the early 16th century, proposed the first modern European heliocentric theory. Copernicus' heliocentric theory had several major technical flaws, including Copernicus' retention of the notion that the orbits of planets were perfectly circular in shape. Nevertheless, the theory served the important purpose of freeing astronomical science from the geocentric viewpoint that held that everything in the solar system revolved around the Earth.