Institutio Oratoria

For we find, more especially in the pages of Cicero, but frequently in Asinius and other orators of that period, quotations from Ennius, Accius, Pacuvius, Lucilius, Terence, Caecilius and others, inserted not merely to show the speaker's learning, but to please his hearers as well, since the charms of poetry provide a pleasant relief from the severity of forensic eloquence.