Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
The statement of fact will be credible, if in the first place we take care to say nothing contrary to nature, secondly if we assign reasons and motives for the facts on which the inquiry turns (it is unnecessary to do so with the subsidiary facts as well), and if we make the characters of the actors in keeping with the facts we desire to be believed: we shall for instance represent a person accused of theft as covetous, accused of adultery as lustful, accused of homicide as rash, or attribute the opposite qualities to these persons if we are defending them: further we must do the same with place, time and the like.
It is also possible to treat the subject in such a way as to give it an air of credibility, as is done in comedy and farce. For some things have such natural sequence and coherence that, if only the first portion of your statement is satisfactory, the judge will himself anticipate what you have got to say in the later part.
It will also be useful to scatter some hints of our proofs here and there, but in such a way that it is never forgotten that we are making a statement of facts and not a proof. Sometimes, however, we must also support our assertions by a certain amount of argument, though this must be short and simple: for instance in a case of poisoning we shall say,
He was perfectly well when he drank, he fell suddenly to the ground, and blackness and swelling of the body immediately supervened.