Rick commented in his blog that in Cicero, we see the first attempt at a comprehensive overview of rhetoric. This is true, and I think it's part of the reason I noticed so much intertextuality. I not only had the sense that Cicero was familiar with Aristotle and Plato (and therefore Socrates), but he goes at length to offer what I might call a lit review.
I am curious about whether or not readers/listeners of Cicero would expect coverage of the major orators or not. In Plato, we saw an acknowledgment of the work done by other men in the Symposium, and in Aristotle we saw a few digs at Isocrates. But besides the Sophist/philosopher battle, I didn't sense the same dependence upon other speeches/orators, etc.
This is making me aware of two major changes: 1)the Roman community is HUGE compared to the Athenian culture which seemed isolated and self-perpetuated and 2)Cicero is the first person who seems to have access to the written works.
As for #2--I'm not sure if this is true. Writing was just becoming an elixir during Plato's time, right? When did written literacy become widespread among the Romans? Aristotle had access to written texts, did he not?
My main question is: was Cicero including his knowledge of other rhetoricians in order to prove his competence in speaking on oratory or was he including them in order to inform the listeners?