Chapter XX: Book IV: Exordium, Narratio, Petitio, Conclusio

The _exordium_ is such a prelude to the statement of the facts as will make the hearer[28] open-minded, well disposed, and attentive.

The reader’s sympathy is engaged by the writer’s reference
to himself, to his opponent,[29] to his reader, or to the
occasion. According to the nature of the subject, the
_exordium_ may be either direct (_principium_) or indirect
(_insinuatio_). Its diction must be fluent, correct, unstudied,
i.e., it must avoid harshness, deviation from recognized
usage, and pomp.[30] Especially must the writer avoid any
language that can be turned against him. To begin with a
proverb, though this is advised by some authors,[31] is to
deviate the _exordium_ from its proper function.

_Narratio_, statement of the facts,[32] should be concise, transparently clear, and plausible (_brevis_, _dilucida_, _verisimilis_). The application of the ancient maxim is to the connection of _narratio_ with _exordium_ by proper conjunctions and in several possible cases. Similarly are set forth the ways of connecting it with the following _petitio_, which is summarily defined. _Conclusio_ in a letter is not, as in a speech, the logical result of proof. Rather it is the satisfaction of whatever expectations have been aroused. It may be affirmative, negative, or conditional, so long as it is a satisfying close. Modes of connecting it with the rest of the letter again have most space.