Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
As examples I may cite the praise of Sicily and the rape
παρέκβασις may, I think, be defined as the handling of some theme, which must however have some bearing on the case, in a passage that involves digression from the logical order of our speech. I do not see therefore why it should be assigned a special position immediately following on the statement of facts any more than I understand why they think that the name is applicable only to a digression where some statement has to be made, when there are so many different ways in which a speech may leave the direct route.