Early solar sySTem models
The earliest model of the solar system showed Earth as the center of our solar system. This model was known as "Earth centered". This model of the solar system did not make much sense because ocasionally, we would see a planet move in retrograde motion, which was basically when a planet moved backwards across the sky. If Earth was really the center of our solar system, this would not make sense. Because of this, early astrnomers pushed for another explanation. In 1543, a Polish scientest by the name of Nicolaus Copernicus came up with the theory that the sun was actually the center of the solar system. This model sparked interest and explained retrograde motion. From 1576-1601 Tycho Brahe supplied evidence to back up this theory. Using Brahe's observations, Johannes Kepler developed a series of laws to support Brahe's evidence. These laws would be known as Kepler's Laws.
(Picture from http://www.fas.org/irp/imint/docs/rst/Sect19/Sect19_2.html)