The solar system was formed from a massive gas cloud, and layouts were observed and refined beginning in the sixth century B.C.E. by early Greek astronomers. Nicholas Copernicus and Galileo Galilei continued observing the solar system well into the Renaissance era, according to About.com.
In 200 B.C.E, Greek astronomer Aristarchus invented a model of the solar system in which the sun was in the middle and the planets rotated around it. This layout was geocentric, or earth-centered. Copernicus published his theory called "The Revolutions of Heavenly Bodies" in 1543 A.D. This theory was later supported in the 1600s by Galilei and Johannes Kepler after the first telescopes were invented.