Another model to go on is the 'True History' written by Lucian of Samosata in the second century C.E. He describes a journey to the Moon, mentions colonies on Venus and on comets, and a war between the Sun and the Moon.
http://www.sacred-texts.com/cla/luc/true/index.htm
If this story only existed in fragments, and the first part (where he admits that the story is not, in fact true) were missing, what would the Von Dannikens of the world make of it?