Institutio Oratoria

The same thing may be noted in music. For after assigning five notes to the lyre, musicians fill up the intervals between the strings by a variety of notes, and between these again they interpose yet others, so that the original divisions admit of a number of gradations.

Eloquence has, therefore, a quantity of different aspects, but it is sheer folly to inquire which of these the orator should take as his model, since every species that is in itself correct has its use, and what is commonly called style of speaking does not depend on the orator. For he will use all styles, as circumstances may demand, and the choice will be determined not only by the case as a whole, but by the demands of the different portions of the case.