Quintilian Institutio Oratoria 5.13.2

[2] As a rule no strong appeal to the emotions is made in refutation. It is not, however, without reason that, as Cicero so often testifies, ¹ the task of defence has always been considered harder than that of prosecution. In the first place accusation is a simpler task: for the charge is put forward in one definite form, but its refutation may take a number of different forms, since as a rule it is sufficient for the accuser that his charge should be true, whereas counsel for the defence may deny or justify the facts, raise the question of competence, ² make excuses, plead for mercy, soften, extenuate, or divert the charge, express contempt or derision. The task of the accuser is consequently straightforward and, if I may use the phrase, vociferous; but the defence requires a thousand arts and stratagems.