We had a question about punctuation in classical Latin and it received some great answers. It left me with one question, though: Are there ancient guides or descriptions of punctuation? I am not looking for modern analyses of inscriptions or other documents, but passages or remarks by the Romans on the topic.
The first thing to note when looking at passages and remarks by Romans about “punctuation” is that it is not always clear at first glance whether they are discussing elements of oral delivery or written marks in a text. “Punctuation” or pungere, after all, simply means to puncture or create a gap which can apply equally to oral or written discourse. There is, of course, overlap as written punctuation can be a guide to the oral delivery of the text. Indeed, most references to punctuation that I have found are in treatises on oratory. Yet the main concern of these writers is that true eloquence should not need written punctuation. The rhythm of the prose and its delivery by a skilled orator should make such aids superfluous.
Thus, while Quintilian writes at length about commas, colons, and periods, he is in fact discussing the pauses and rhythm of speech. Cicero, too, is typically concerned with elegant oratory rather than punctuation of a text. So, when he speaks of interpuncta, he is often speaking of pauses between words (interpuncta verborum De Oratore III.XLVI.181), pauses between ideas (interpuncta argumentorum De Oratore II.XLI.177), or pauses in which to catch one’s breath (interpuncta intervalla, morae respirationesque Orator XVI.53).
Nevertheless, Seneca’s use of interpungere clearly refers to written punctuation:
nos etiam cum scribimus interpungere adsuevimus / but we [Romans as opposed to Greeks] even when writing have become accustomed to punctuation (Epistles, XL.11)
This passage is interesting because Seneca's argument is that Romans have need of punctuation precisely because of the way they speak, revealing again that overlap between the spoken and the written word. This overlap, therefore, must account for why the same terms are used (confusingly) to describe the form of both the spoken and the written text.
When Cicero refers to written punctuation, it is disparagingly and he explicitly contrasts the "natural" pauses (interpunctas) of the orator's speech with the written prompts of a copyist (notis librariorum):
interspirationis enim, non defatigationis nostrae neque librariorum notis sed verborum et sententiarum modo interpunctas clausulas in orationibus esse voluerunt / for they wanted a pause for breathing not because we were tired or because of the copyists’ marks but because of the pointed/distinct endings of words and sentences (De Oratore III.XLIV.173)
His comment, mentioned above, about the interductu librari (Orator LXVIII.228) conveys the same contempt for written punctuation.
A passage in Quintilian is often interpreted by scholars as alluding to the marking up of texts in order to help young boys learn how best to read them aloud:
superest lectio: in qua puer ut sciat ubi suspendere spiritum debeat, quo loco versum distinguere, ubi cludatur sensus … / reading remains [to be discussed]: in this a boy in order to know where he ought to take a breath, at which place to divide the verse, where the sense ends ... (Institutio Oratoria 1.8.1)
Distinguere certainly does mean to separate, divide, or to mark the pauses in a discourse (Lewis & Short) but it isn’t clear to me that Quintilian is speaking here of written punctuation as the passage seems to be discussing reading aloud.
However, this use of distinguere is definitely used by Suetonius to refer to written punctuation. Here he describes Marcus Valerius Probus' hobby of writing in copies of texts:
multaque exemplaria contracta emendare ac distinguere et annotare curavit / after gathering many copies, he gave his attention to correcting and punctuating and annotating them (Lives of Illustrious Men: On Grammarians XXIV)
So, while I couldn't find any extended discussion of punctuation in the works of Roman authors, I think we can at least establish that written punctuation was not a routine addition to texts but that the concept of punctuation existed. Further, when punctuation was added, it was to mimic or facilitate the oral production of a text. This probably explains why the terminologies are the same. I think we can also see that there was resistance to what was perceived as a "crutch" for orators. The arguments of Cicero and Quintilian support the argument of A. W. Hodgman ("Latin equivalents of punctuation marks" - summarised here: punctuation in classical Latin ) that the very structure of Latin words and sentences "has very clear equivalents for some of our punctuation marks" making punctuation marks unnecessary (in the eyes of some).