Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
In this connexion I may cite the practice of comic actors, whose delivery is not exactly that of common speech, since that would be inartistic, but is on the other hand not
So too we shall have to put up with certain inconveniences arising from the nature of our fictitious themes; such drawbacks occur more especially in connexion with those numerous details which are left uncertain and which we presume to suit our purpose, such as the ages of our characters, their wealth, their families, or the strength, laws and manners of the cities where our scenes are laid, and the like.