This study is a continuation of a collaborative investigation undertaken by Miss Mary A. Grant of the University of Kansas and myself. In Volume XXXV of the Harvard Studies in Classical Philology, pp. 1-74 we published an article entitled Cicero's Orator and Horace's Ars Poetica.1 The present study deals along similar lines with the relationship between the De Oratore of Cicero and the Ars Poetica of Horace. As in our earlier study, the inventio is essentially Miss Grant's; the dispositio and elocutio are mine. She is not responsible for any errors of omission or commission in the present study.
In the proœmium of the earlier study2 I sketched the broad outlines of a stemma of rhetorical content, and pointed out that my primary concern was rather with the community of ideas and commonplaces operative within the field covered by the stemma than with verbal resemblances. Once more we shall be concerned rather with the horizontals and diagonals of cross relationship than with the vertical lines which plot the descent of rhetorical, literary, or poetic theory.
It is important to remember that the Romans were in the main introduced to the study of rhetoric, not through the texts of the sophists, of Plato, Isocrates, and Aristotle, but in part as pupils of Hellenistic and Greco-Roman rhetoricians, in part by the perusal of the τέχναι ῥητορικαί. A study of the commentary of Heinze-Kiessling upon the Ars Poetica of Horace should convince the most skeptical that this work is steeped in Hellenistic rhetoric. I need only refer my readers to the introduction of Lejay's masterly edition of Horace Satires and to the prefaces to the individual satires passim as evidence for the influence of Cicero's philosophical and rhetorical works upon the Satires of Horace.3 I must omit a consideration____________________