Quomodo historia conscribenda sit
Lucian of Samosata
Lucian, Vol. 6. Kilburn, K., translator. London: William Heinemann, Ltd.; Cambridge, MA: Harvard University Press, 1959.
Again, in putting words together one should cultivate a well-tempered moderation, without excessive separation or detachment—for that is harsh—and not, as most people, almost link them by means of rhythm; the latter deserves our censure, the former is unpleasant to the audience.
As to the facts themselves, he should not assemble them at random, but only after much laborious and painstaking investigation. He should for preference be an eyewitness, but, if not, listen to those who tell the more impartial story, those whom one would suppose least likely to subtract from the facts or add to them out of favour or malice. When this happens let him show shrewdness and skill in putting together the more credible story.
When he has collected all or most of the facts let him first make them into a series of notes, a body of material as yet with no beauty or continuity. Then, after arranging them into order, let him give it beauty and enhance it with the charms of expression, figure, and rhythm.