The notion that the Earth orbited the Sun was an ancient one developed by Aristarchus or Hipparchus, or both, depending on whose account you believe. Both studied gravity.
But it wasn't until recently, during the 16th century, that scientist Nicolaus (nik-oh-LAY-us) Copernicus (koh-PERN-ih-cuss) proved that the Sun was at the center of our solar system, and he was able to predict the movements of the parts of solar system as they moved around the Sun.
It wasn't until around the start of the 20th century that astronomer Edwin Hubble and others proved that the Sun was not at the center of the Universe, either.