Ideas concerning the origin and fate of the world date from the earliest known writings; however, for almost all of that time, there was no attempt to link such theories to the existence of a "Solar System", simply because almost no one knew or believed that the Solar System, in the sense we now understand it, existed. The first step towards a theory of Solar System formation was the general acceptance of heliocentrism, the model which placed the Sun at the centre of the system and the Earth in orbit around it. This conception had been gestating for thousands of years, but was only widely accepted by the end of the 17th century.