Quotiens autem prooemio fuerimus usi, tum sive ad expositionem transibimus sive protinus ad probationem, id debebit in principio postremum esse cui commodissime iungi initium sequentium poterit. illa vero frigida et puerilis est in scholis affectatio, ut ipse transitus efficiat aliquam utique sententiam et huius velut praestigiae plausum petat, ut Ovidius lascivire in Metamorphosesin solet; quem tamen excusare necessitas potest, res diversissimas in speciem unius corporis colligentem: oratori vero quid est necesse surripere hanc transgressionem, et iudicem favere qui ut ordini rerum animum intendat etiam commonendus est? peribit enim prima pars expositionis si iudex narrari nondum sciet. quapropter, ut non abrupte cadere in narrationem, ita non obscure transcendere est optimum. si vero longior sequetur ac perplexa magis expositio, ad eam ipsam praeparandus iudex erit, ut Cicero saepius, sed et hoc loco fecit: “paulo longius exordium rei demonstrandae repetam, quod quaeso, iudices, ne moleste patiamini; principiis enim cognitis multo facilius extrema intellegetis.” haec fere sunt mihi de exordio comperta.
(Quintilian, Inst. Or. 4.1.76-79)
However on all occasions when we have employed the exordium, whether we intend to pass to the statement of facts or direct to the proof, our intention should be mentioned at the conclusion of the introduction, with the result that the transition to what follows will be smooth and easy. There is indeed a pedantic and childish affectation in vogue in the schools of marking the transition by some epigram and seeking to win applause by this feat of legerdemain. Ovid is given to this form of affectation in his Metamorphoses, but there is some excuse for him owing to the fact that he is compelled to weld together subjects of the most diverse nature so as to form a continuous whole. But what necessity is there for an orator to gloss over his transitions or to attempt to deceive the judge, who requires on the contrary to be warned to give his attention to the sequence of the various portions of the speech? For instance the first part of our statement of the facts will be wasted, if the judge does not realise that we have reached that stage. Therefore, although we should not be too abrupt in passing to our statement of facts, it is best to do nothing to conceal our transition. Indeed, if the statement of fact on which we are about to embark is somewhat long and complicated, we shall do well to prepare the judge for it, as Cicero often does, most notably in the following passage: “The introduction to my exposition of this point will be rather longer than usual, but I beg you, gentlemen, not to take it ill. For if you get a firm grasp of the beginning, you will find it much easier to follow what comes last.” This is practically all that I can find to say on the subject of the exordium. (tr. Harold Edgeworth Butler)