There are three virtues of a narration, brevity, probability and
perspicuity. The epic poet should diligently strive to attain the second
and third, and may learn how to do it from the masters of rhetoric.[189]

Thus a poet should seek in an epic the same qualities which an orator is
supposed by classical rhetorics to strive for in the statement of facts of
his speech.[190] Furthermore, says Pontanus, one can write very good
poetry by paraphrasing orations in verse.[191] No wonder Luis Vives
complained in his _De Causis Corruptarum Artium_,

The moderns confound the arts by reason of their resemblance, and of two
that are very much opposed to each other make a single art. They call
rhetoric grammar, and grammar rhetoric, because both treat of language.
The poet they call orator, and the orator poet, because both put
eloquence and harmony into their discourses.[192]

From this brief summary, derived for the most part from the exhaustive
studies of Vossler and Spingarn, one may recognize some of the rhetorical
elements in the theories of poetry current in the Italian renaissance. The
Aristotelian studies of the Italian scholars very largely accomplished the
overthrow of the mediaeval theories of poetry and the re-establishment of
the sounder critical theories of classical antiquity. Their service to
subsequent criticism has been so great and their critical thinking on the
whole so sound that it may seem ungracious to call attention to a few
cases where they were unable to shake themselves entirely free from the
mediaeval tradition of classical rhetoric.