 Theophrastus and Aristotle, then, were used in this way. An example: The chapters in Aëtius (Placita 3.9–15) and Cicero (Academics 2.122) dealing with a number of various and occasionally even bizarre views concerning the position, motion, shape, etc. of the earth in the last resort patently derive, as to their main themes and oppositions and even as to some telling details, from a chapter in Aristotle’s On the Heavens (2.13) (Mansfeld 1992). Cicero here mentions Theophrastus by name; he therefore may well be involved too, as an intermediary source. But we have no further evidence concerning his contribution in this particular instance.