A late Roman author, Flavius Magnus Aurelius Cassiodorus Senator, integrates stemmata into his writing in a remarkably smooth way. His Institutiones, the "introduction to the divine and secular readings" [*]Translations: Jones, Leslie Webber. An introduction to divine and human readings. New York: publisher, 1946. Halporn, James W. Institutions of Divine and Secular Learning. Liverpool: University Press, 1992, 2006 Bürsgens, Wolfgang. Institutiones Divinarum et Saecularium Litterarum = Einführung in die geistlichen und weltlichen Wissenschaften. Freiburg: Herder, 2003. , written about 562 AD, contains 37 stemmata (full list) [*]Eight of these are printed in the critical edition: Cassiodorus Senator, Flavius Magnus Aurelius. Cassiodori Senatoris Institutiones, Mynors, Roger A.B. (ed). Oxford: Clarendon, 1961. Mynors picks apart all the others, where only one degree of division takes place, and prints them as simple lists. [*]See also the tabulation of the stemmata in Orofino, Giulia. Da Montecassino a Nonantola: La tradizione illustrativa delle Institutiones di Cassiodoro, in Il monachesimo italiano dall?et� longobarda all?et� ottoniana (secc. VIII-X), Convegno, Nonantola, 9-13 September 2003. <> (live link below). .

Unlike diagrams which illustrate a text, these stemmata are the text.[*]For this reason, it is unfortunate that Mynors' critical text and the modern translations reformat all but eight of them into plain text. See: Gorman, Michael: The diagrams in the oldest manuscript of Cassiodor's Institutiones. In: Revue b�n�dictine 110 (2000), 27-41.. They introduce brief analyses of the elements of philosophical, rhetorical and mathematical theory, showing how the component terms interact with one another. Each stemma passage employs only a few connecting words (A is made up of X, Y and Z ... A or B ... several A ...) and instead uses mise-en-page to convey how those terms relate to one another. Without the stemmata as an introduction and structure, the discussion that follows each would make little sense, since each follow-up explores the deeper meaning of the terms, mostly without repeating the inter-relationships.

In his book, aimed at what one might describe as an undergraduate readership, Cassiodorus is casual in his employment of the stemmata, without any kind of apology or instructions for their use. This strongly suggests that a familiarity with this kind of sketch must have been expected of an intellectually literate person in the Roman world.

Cassiodorus seems to be describing the teaching utility of the stemma in a passage of his preface (2, praef. 5): duplex quodammodo discendi genus est, quando et linealis descriptio imbuit diligenter aspectum, et post aurium praeparatus intrat auditus. (Possible translation: Learning is a dual process: the visual mind first acquires the exact context through a drawn figure, so that an attuned aural perception can grasp the subsequent discourse [*]This interpretation of linealis descriptio was proposed in Esmeijer, Anna Catharina. Divina Quaternitas. Utrecht: Univ., Diss., 1973. Here: page 46. See also Klapisch-Zuber 1, page 30 and note 62. The same topos is found about 25 years earlier in the Institutions of Justinian introducing the arbor consanguinatis diagram: sed cum magis veritas oculata fide quam per aures animis hominum infigitur ... Inst. 3. 6. 9. Compare also Boethius' use of the word descriptio: ...rei subjecta descriptio sub oculis ponat exemplum..) It is curious to note that modern cognitive research has offered confirmation of that finding:

To be maximally effective, the diagram should be examined before the reader encounters the relevant text, in part because the diagram helps to organize the text and in part because the reader may try to visualize what the text is describing, and the results may not match the diagram. [*]Chabris, Christopher, and Stephen M. Kosslyn. ?Representational Correspondence as a Basic Principle of Diagram Design.? Knowledge and Information Visualization (2005): 185?186.

The sketches must have been a familiar device in the classroom in his his youth, and perhaps Cassiodorus employed them in his lectures to the young monks whom he began to train in his old age at his own religious foundation at Vivarium in southern Italy. He clearly did not devise these figures himself. In fact, in one instance, he offers an "official" Roman law-school stemma and tacks his own note on it to say that he considers the concept of translatio (a party at law contending that an opponent or a judge has no standing to file suit or try a case) to be wrongly classified. While he does position this concept of "non-standing" in its pre-ordained place, he attaches a protesting block of text on top of it, a kind of early post-it note, which bursts the visual harmony of Cassiodorus's stemma.

There are two separate styles of stemma in the various manuscript copies dating back to the 9th century and even before. In one tradition, apparently found throughout what Mynors calls the Group I manuscripts, the root of each stemma is represented by a figure such as a wild animal or human face, the precise symbolism of which has excited a certain amount of modern debate.[*]Wirth, 298. In the other tradition, associated with the Group III manuscripts, there is no figurative adornment, and the stemma lines generally spray out from a blob or dot.

Several features of the stemmata (full list) in the earliest manuscripts are striking:

In the Group I stemmata, each node is topped by a kind of lid, or, as Wirth humorously calls it, an inkwell.[*]Wirth, 297 This symbol's meaning and origin are not known, but it would seem to be part of the system of Group I imagery and not to be a general rule of 9th-century stemma design. The St. Gall manuscript also has a kind of funnel below each node. The animals and other figures are usually placeholders for the root term, which is outside the diagram, being found in the text block above it. We do not know if these animal-lid-and-funnel stemmata are of Roman origin.

I have made some sketches of the Group I and the Group III stemmata. An approximate translation of each node into English is provided. Some shifting and stretching was needed to allow the use of legibly large text. Where the text is too small, one can zoom in to read it.

In the Group I illustration, I have dispensed with the animals, lids and funnels and have concentrated on showing the lines and orientation. The original of No. 7, the status causarum stemma at the left, categorizing issues of fact and law, can be viewed in the online library of Swiss manuscripts and comes from a 9th-century St. Gall Abbey codex. It is a notably untidy arrangement. In the original, the connecting lines are often misplaced or at strange angles.[*] St. Gall Cod. Sang. 855, fol 208r; Group I, code-name S in Mynors' stemmata codicum. The stemma at right, No. 11, categorizes rhetorical argumentation. It is sketched here to illustrate the mixed and peculiar forms chosen by the scribe for the sub-stemma connecting lines. The original is an early 9th-century manuscript at the Biblioth�que Mazarine in Paris (see the St Gall version for comparison).[*]ms. 660, fol. 114r; Group I, code-name M in Mynors' stemmata codicum. Also reproduced in Wirth as figure 17a.

As for the sketches of the unadorned or Group III type, I have not been able yet to see a wider range of Institutiones manuscripts containing them. The stemma on the left (No. 12, the divisions of philosophy) was published by Wirth.[*]Formerly Sir Thomas Phillipps Library, Ms. 16278, apparently auctioned in New York in 1979. Mynors Group III, code-name λ. Mynors states that the precursor of Group III was used before 819 by Rabanus Maurus (xxxiv) and that it seems most likely this lost precursor dates from some time in the 8th century (xxxix). and has a straight-line counterpart in the manuscript St. Gall 199. The one on the right (No. 30, an arithmetic stemma) can be seen in its original red ink in that 9th-century manuscript from St Gall (online).[*]St. Gall Cod. Sang. 199, fol ---; Mynors Group III, code-name θ. Both Group III stemmata are notable for their spider-like character, with a small round body at the centre of the "legs". Adaptations and a (possibly non-Cassiodorean) additional diagram, such as a five-generation stemma of the qualitas generalis, appear in the Group III manuscripts.[*]That stemma is a subset of the genuine Cassiodorean stemma number 4, but with somewhat altered wording. See the note below my list as well as Mynors, xxxvii.

The antiquity of the Group-I-stemma style is uncertain. The oldest extant version is at Bamberg and has been dated to the second half of the 8th century, 200 years after Cassiodorus wrote his book.[*]Staatsbibliothek, Msc. Patr. 61 The Bamberg codex's Italian scribe was not the inventor of the stemmata or their decoration and was clearly copying them from a book penned years or decades earlier. The Italian scholar Giulia Orofino compared the animal figures in several manuscripts in 2003 and argued that not only the stemmata, but the motifs too, are Cassiodorus's own work, though significantly modified in the course of decades of copying.[*] Orofino (see note above); This contradicts Klapisch-Zuber, 30, which insists that the symbolic animals were a Carolingian invention, originating long after the death of Cassiodorus.

The unadorned design always appears in the secondary editions of Cassiodorus's work (the so-called interpolated versions), where passage from Cassiodorus and other authors have been combined into books of readings. It is possible that the unadorned stemma design is the creation of the revisor, perhaps long after the death of Vivarium's founder . But it is also conceivable that both types of stemma are the work of Cassiodorus himself, with the first, plain design appearing in an early draft of his book, perhaps an echo of the educational methods of his youth, before he proceeded to a more elaborate version, of his own devising, for a second edition of his book.

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