Mind's Eye Has Been Published

When were family-tree diagrams invented? My new book, Mind's Eye: How One Ancient Latin Invented Our Way to Visualize Stories, uncovers the progenitor of today's graphic timelines and trees in an ancient three-meter-wide chart of history.

Hidden in plain sight, the Great Stemma -- a Roman masterpiece -- has never been honored at book length before.

The Great Stemma was not only a vast visual abstraction of the march of time from Creation as far as the birth of Jesus Christ, but also marked a swerve in civilization towards exploiting our visual perception as an extra tool for thinking.

I argue that diagrams and visual displays exploit the computing power of human vision to short-cut our reasoning tasks. Cognitive science is only now able to grasp what a major shift in human culture this was. My research places that creative leap in the ancient world.

I foreshadowed Mind's Eye two years ago (when the book's working title was "Expositor" and I was still following up some loose ends in the inquiry). Since then, I have added some great cover art (the theme comes from Neptune's Necklace, a wondrous seaweed from the South Pacific) and converted the manuscript to e-book format. A print version may follow.

Here's the link which leads to stores where you can buy Mind's Eye at a low introductory price: https://books2read.com/PigginMindsEye (to which I add a modest plea: buy from one of the non-Kindle stores, where the price to you is the same, but I get a bigger royalty!)

Mind's Eye can be read rapidly, by skimming the 117 illustrations and checking out the QR links. Or it can be savored as an 88,000-word narrative in which I narrate how I brought this neglected graphic to light.

Via Appia Found on Satellite Image

The Appian Way is perhaps the world's most celebrated road. On the outskirts of Rome it is a major tourist attraction. I have just discovered you can see some of its far reaches on photographs from space.

The Way seems to be the source of a common misconception in the English-speaking world that all Roman roads were solidly paved and ran straight as a laser, up hill and down dale, never yielding to the lie of the land. Beyond Terracina, much of the Via Appia was neither paved nor straight, but wriggled along long-worn prehistoric ridgeway routes, where the ground was drier (and harder) and the traveler had the best chance of spotting approaching attackers, whether they were bandits or bears.

Begun under the direction of Appius Claudius, a consul, in 312 BCE, the Via Appia initially connected Rome to Capua near Naples. Later it was extended to Brindisi on the Adriatic Coast. It was any physical traces of this latter extension that I was hoping to find while on a visit last week to Italy.

We were staying in the newly elegant city of Matera which is dolling itself up to be one of two European Capitals of Culture of 2019. In Roman times, Matera was just a remote warren of hand-hewn caves, never mentioned in the ancient sources. Perhaps it was a refuge of the above-mentioned bandits, who could murder a merchant on the Via Appia at dusk and carry the booty 15 kilometers away to the caves to hide it, safely holed up by midnight like the Ahlbergs' brigands:

Near Matera one finds two modern highways named Via Appia. The one beginning from Ferandina, national highway SS7, and proceeding via Matera to Massafra is a fake, although it too terminates at Brindisi. The other, Puglia provincial road SP28, marked "Strada Provinciale Appia" on maps, is, in some stretches at least, the real thing.

Recent articles by Luciano Piepoli dispense with the armchair scholarship (mainly German) about this part of the Via. They assemble new hard archaeological evidence about its course and stage-stops. Unfortunately Piepoli does not provide GIS geolocations (this ought to be prescribed by the style guides of every journal dealing with historical geography). He writes:

The Appian Way, at the exit from the current town of Gravina in Puglia, begins its path in a south-easterly direction near Scomunicata and, after having touched the localities of Graviscella and Ponte Padule Cardena, reaches the rocky outcrop of the Murgia Catena, located about 7 km southeast of Altamura. The road runs along the southern slope of this last location to Iesce, where there are the remains of an important settlement that had been abandoned by the 2nd century B.C. On the territory of Altamura, in a flat section between the southern slope of the Murgia Catena and the hillock of Montepovero, the projecting traces of wheel ruts are visible in the rocky surface for a length of about 200m and a total width of more than 30m, forming multiple lanes. Although they are not contemporary with one another, it appears highly probable by virtue of their topographical location that some of them must derive from the consular Via Appia. (My English, helped by Apple and Google Translate).

Hoping to see these traces of the wheels of ancient or medieval carts, we stopped our car on the shoulder of the SP28 at what we thought was the spot. Since a narrow lane of wheat was growing there on the verge of the road itself, we searched the rocky field behind it, but to no avail. On the point of giving up, and after nearly stepping on a sturdy snake, I finally discovered the ruts further up the road.

In the 50-second video above you may hear a cicada and will see the colorful wild flowers of a southern Italian spring including tall fennel, all growing in the dirt that has collected in the ruts.

The most pronounced track is at the left, close to the dry-stone wall. There are no doubt specialists who could estimate from the wheelbase whether this track is ancient or medieval. A second, shorter bunch of tracks can be found about 50m further down the hill (in a 24-second video). I have uploaded videos of both to my YouTube Channel.

The greatest surprise came later: these ruts are visible on common garden satellite imagery. When I studied the same location on Google Maps later, I was amazed to see the big set of ruts quite clearly at the location 40.76424, 16.61516 (tip: copy just this to any sat-nav or mapping app to find it):

As far as I know, this remarkable, aerially visible archaeological site is not listed on any of the ancient geographical portals such as the Digital Atlas of the Roman Empire, Pelagios or Vici. I can see how to add it to Vici (and will add it later), but I must admit that I have no idea yet how to contribute it to the former two. They do not offer any "guide for dummies" instructions.

These stone remains are no longer 30 meters wide, since the new road passes through the middle, and they do not seem to have gained any legal protection, although the feature is surely known locally. The IGM map of 1919 (reproduced as British AMS M791 of 1939) labels a nearby stretch of the road "od via antica Via Appia" (I don't know what "od" means).

Piepoli relies on a survey of the area by the great aerial archaeologist of the 1920s to the 1950s, Giuseppe Lugli, so I presume these remains are mentioned in Lugli's books or articles. As far as I can tell, they are the only surface evidence left of the ancient Via Appia between Gravina and Tarento.

The fact that wheels ran across bedrock here is an indication that the highway was unpaved. A few kilometers away, the route has been archaeologically excavated. Piepoli writes:

Near Masseria Capitolicchio Vecchia, recent excavations conducted by the Archaeological Superintendency of Puglia have highlighted a short stretch (about 200 x 4.90 m) of a road - of the glareata type - interpreted, on the basis of the construction technique, orientation and topographic context, as a segment of the Appian Way [Mattioli, 2002]. An interesting fact which emerged during the excavations is that the roadway is partially obliterated by a layer of relative collapse likely due to a structure located near the road axis. The ceramic finds and coins found can be dated between the end of the 2nd century BC and the 3rd century AD, which could be considered as a terminus post quem for the abandonment of the Via Appia in this section.

The simple glareata road had a base of stones, built up to a sand or gravel surface, and would be kicked or ground apart by heavy traffic if it were not maintained. This is probably what happened at 40.76424, 16.61516, exposing the bedrock to the grinding of cart and carriage wheels. Above, I mentioned a narrow crop of wheat growing in the queen's acre (the roadside). It too is clearly visible in the space imagery, and occupies what seems to have once been a ford through a seasonal stream, the Vulle. No doubt the silt, organic particles and the churning of the wheels created a fertile slough in this rocky landscape which, as the 1919 map shows, travelers had to edge around.

Most of the Via Appia in this area follows the watershed. Here's a more open location, looking towards the Murgia Catena from the north-west, where you may be able to see that the land slopes very lightly away to both sides.

To the left of this spot, the drop to the base of the valley is quite substantial, as the next image shows:

In an article this year, the scholar Tønnes Bekker-Nielsen compares the posterity of this southern Via Appia built in the 3rd century BCE to the highly engineered Via Traiana built with cuttings and bridges in the 2nd century CE. The bridges ultimately fell down, whereas the prehistoric footpaths and droving tracks along the watersheds proved indestructible. The self-maintaining character of ridgeway routes even after all their gravel has eroded away is the reason that the Via Appia remained in continuous medieval and modern use and was then resurfaced in the 20th century:

For the Roman traveler, the Via Traiana was a significant improvement. It was shorter, had far fewer inclines and declines and was less vulnerable to snowfall. But despite the many advantages of the Via Traiana, it is the Via Appia which has survived to this day. An estimated 90% of the total length of the Appia is still in use as graveled or asphalt road. Large portions of the Via Traiana, on the other hand, are overgrown and impassable. (My assisted translation from the Danish.) 

Bekker-Nielsen, Tønnes. ‘Romerske Veje i Syditalien: Via Appia Og via Traiana’. Vejhistorie, 2018. Academia.edu

Piepoli, Luciano. ‘Blera e Sub Lupatia (It. Ant. 121,4-5): Proposte per l'identificazione di due stazioni itinerarie lungo il tratto apulo della via Appia’. In Statio amoena: Sostare e vivere lungo le strade romane, edited by Patrizia Basso and Enrico Zanini. Oxford: Archaeopress, 2016.  Academia.edu

———. ‘Il percorso della via Appia antica nell'Apulia et Calabria: Stato dell'arte e nuove acquisizioni sul tratto Gravina-Taranto’, in Vetera Christianorum, 51, 2014, 239-261’. Academia.edu.

Greatest Brain Hack of All Time

Human beings are mostly quite good at remembering lots of faces. We automatically classify faces by shape and complexion. We mentally associate similar looking faces into families and groups. After seeing a face, we rapidly assign that person to a known category.

But if we only have strangers' names and can't see their faces, how do we begin to encompass who they might be and where they belong? Human beings are terrible at remembering multitudinous connections between abstract things like names or ideas. Without a visible presence, these are hard to grasp.

Oddly enough, storing and retrieving data about connections is a ridiculously simple task to design into a computer program. But for most people, it can take hours of reciting and revision to learn by heart how a hundred facts or words or values are interconnected. We are not built to do that well.

About 2,000 years ago, some very clever people invented a method to get around this issue. They looked for a mechanism in the human brain which operates in some other context to solve similar problems. To understand what they discovered, let's imagine we go to some beach resort for the first time.

In the first hour, you figure out the path down to the beach, recognizing some landmark you need to pass on the way, like a restaurant. You immediately note a couple of other landmarks like an especially ugly hotel and an ice-cream booth. As you walk around the village, you discover a caravan park behind the ice-cream joint and a bus-stop past the hotel. In time, you realize that the bus-stop is in a street which leads to a boat-hire place and out to the main highway.

What's developing in your head is a mental map full of branching connections. Now strangely enough, most of us can remember hundreds of landmarks and waypoints when we are out and about. We retain them much more easily than we remember interconnections between abstract facts.

So the solution devised back in the Roman Empire was a hack. If you pretend to yourself that abstractions are landmarks along forking paths, your innate guidance system will do the heavy computing work for you, and aid you to grasp the interconnections among the concepts.

All you have to do is draw a branching path, plant the facts along it, and then walk this path with your eyes. This is a drawing of the descendants of Leah, a biblical woman, as it was devised around the year 400. The manuscript you are looking at (Florence, Plutei 20.54) was accurately copied from it about 600 years after that.

You might look at this and think: OK, that's just a family tree. For us in the 21st century, diagrams where you walk paths with your eyes are common and unremarkable. But back then the invention was very new. It had not previously been realized that abstractions like a genealogy of three generations could be visualized in this way.

Because this hack was very new, the design had to respect where its readers were at. Nobody was yet educated in how to read these abstract diagrams. Readers only had their instinctive human ability to walk branching paths and find their way by landmarks back to where they started.

In our mental maps of the world, almost anything can serve as a landmark. Every waypoint has a unique appearance, but is similar in its function. So in the Roman abstract diagram, every node had unique content, but was standardized in its circular shape.

In our mental maps, it's easy to learn waypoints, but hard to learn bearings. We imagine the waypoints of every path as one behind another and we ignore slight changes of direction. So in a Roman abstract diagram, the nodes are arranged in straight lines with as few turns as possible.

This Roman diagram was only recently re-discovered. It's the only chart of its type to have been copied in the Middle Ages. It's now the only one surviving from antiquity. Because the Roman diagram is stripped down to the bare essentials, it shows the essence of how we learned to harness the brain to do something new: grasp abstract facts by treating them as if they were landmarks on paths.

This may be the greatest brain hack of all time, a kludge that's so good that we no longer even realize we are harnessing our guidance systems to do something they were not designed to do.

And because it was devised for a world that did not yet use visualizations, it provides valuable clues to how all mental maps work in humans, and indeed in most animals, and even in many insects.

We humans are not as good at thinking about abstractions as we pretend to be. But if we had not adapted our mental navigation machinery to help in the task, we would be far worse at it.

Bridge at Blumau

In a post one year ago, I described the ancient road through the Eisack gorge in the north of Italy. The other day I took a closer look at its major surviving Roman feature, the Bridge at Blumau or Prato all'Isarco. In this post I will use the German name of the town, since this community is in a German-speaking area.

As I have already explained, this road possessed enormous geopolitical importance, providing the quickest communication route to move troops, intelligence, materiel and goods between Germania and Italia through the Alps. One might argue that every bridge on this north-south route possessed equal importance, but the Blumau crossing, deep inside a narrow, obstructed gorge, was surely the most challenging and most expensive to build, maintain and defend.

Other important crossings like that at Waidbruck (Ponte Gardena) could be re-sited, or may even have had back-ups, but the Bridge at Blumau was quite simply irreplaceable: there was almost no other position at Blumau in which it could be be placed, and pontoons could not be used. Without the bridge, this all-seasons route would have been impassable. Any north-south communication, weather permitting, would have required at least an extra day via the Ritten Plateau or Völs route, or at least three extra days, via the more westerly Via Claudia Augusta over the 1,500-metre Reschen Pass. See my map.

All that remains of the bridge today is a stone abutment, which stands on the left or south bank of the river. This important monument is not signposted in any way, and it is fairly difficult to get a view of. You can lean right out from the parapet of the existing concrete bridge and see at least part of the stonework from above (in the bottom left quarter of this picture, which you can enlarge by clicking):

A better view is obtained by driving down an asphalted lane on the right bank, and scrambling over steep loose soil to the water's edge, down-river from the bridge. Here it is possible to stand on a sandbank and peer through fronds of trees, obtaining a view of how the abutment curves up into the beginning of an arch. Eight layers of stone remain. It may be that some of the collapsed bridge is still here in the river-bed.

The next picture shows the structure, with the arch of a 20th-century concrete bridge above it. The remains are in shadow at the centre of the picture. It might have been better to wait all day until the sunlight was not so bright and then take a picture, but my dear wife and son came along for this expedition and we had some other pleasures such as hiking to also accomplish that day, so this picture will have to do:

Probably the most recent professional description of one of Late Antiquity's most neuralgic sites is that by Vittorio Galliazzo, the great scholarly authority on Roman bridges, who examined the structure in 1999. I do not know much Italian, so I have used Bing and Google Translate to essay the following rough translation from pages 64-65 of his 2002 article, Ponti e Forme di Attraversamento di Corsi d’Acqua dell’Alto Adige in Età Romana. Please let me know if you can improve or correct the translation:

Near a site that has already yielded a milestone from the reign of Maxentius (CIL V 8054 = 463 IBR), the left abutment of an ancient bridge on the old road through the Eisack Valley, together with a section of an arch almost up to its waist, was found in 1930 about 5 kilometres east of Bolzano during reconstruction of a bridge that forms part of the Brenner Highway. Further investigation at the end of 1988 by Dr. Lorenzo Dal Ri of the Archaeological Heritage Office of Bolzano Province confirmed that these remains were probably Roman. An architect, Andrea Perin, subsequently suggested his own reconstruction in a sketch based on the scant reliable information available and a good deal of hypothesis.

From the details that follow, one understands what an engineering challenge the structure posed for its designers and builders: it  had to cross high-volume rapids that are susceptible to flash floods. Land access to the cramped site is blocked from north and south. No boats could be used. A huge wooden frame had to be assembled to hold the large number of wedgestones during construction.
No piles could be driven: the footings had to be carved out of solid rock.

The section that follows is awkward to follow without any picture, so I have inserted letters into Galliazzo's account in square brackets, so that you can see in this detail from my photo which layers he is talking about:

The abutment is approximately 4.50 m wide at its base and consists of four rows of blocks of compact yellowish stone of modest thickness [B1, B2, B3, B4] which protrude on the upstream side, as if to form a protective flank with the aid of the carefully modelled porphyry stone of the riverbank. The abutment is fitted into a cavity specially hollowed out of the dark porphyry rock [P] on the left bank, evened out as need be with sandstone slabs. The sector of arch, which is about 4 metres wide, tops this support structure and likewise consists of yellowish blocks of porphyry. One sees four rows of wedge-stones, three of them [A1, A2, A3] nearly intact and one fragmented [A4].
All the surviving structure of the abutment is in big chiselled blocks, tied with leaded iron clamps. Several stones, especially the upstream ones in the third and fourth row [B3, B4], have rusticated faces with listello or refesso drafted margins. The arch segment appears to have had an intrados in opus vittatum consisting of rather small blocks joined with hard lime.
From what I could see directly during a first inspection in 1994 and a subsequent survey in 1999, the first row from the bottom in the remaining sector of the arch [A1], that is to say counting up from the join, comprised four quadrangular, regularly dimensioned blocks, with a fifth flanking them upstream while a sixth downstream from them was tailored to fit into the “living” rock. This layer was surely used at the time of construction to support a hoop-shaped wooden scaffold and then probably re-used as the footing for the wooden beams of the later medieval bridge, which was no longer a stone arch but probably a wooden truss (i.e. a series of vertical stays supporting a horizontal wooden superstructure). At about 10 and 21 metres respectively from this ancient abutment, you can see the remains of two piers in the bed of the Eisack River on which uprights of the scaffolding for the boxing to construct the 1928-1930 concrete bridge stood before they collapsed.

Galliazo's article includes two black and white photographs evidently taken in winter when there was less vegetation obscuring the view. He also reproduces Perin's sketch although he repudiates its veracity. Galliazzo concludes with the following general assessment of the structure:

It seems that the whole bridge, from abutment to abutment, had a length of about 33-34 metres which could be feasibly crossed not with three arches as has been proposed in the draft reconstruction, but with just two asymmetrical arches. This would result in a bridge similar to that at Merano with arches supported on sturdy abutments built into the rock of the banks and one pier of considerable proportions outside the river current: the greater of the two arches would have been on the left of the river and would have needed to have a length of about 18-20 meters to straddle the channel, while the lesser arch would have had an opening of less than 8 meters and would have probably provided an extra discharge during floods to better withstand the water pressure.
As regards the dating of the structure, the arrangement of the stone blocks and the overall impression given by the remnant of the abutment would suggest engineering of the Imperial if not of the Late Antique period, perhaps replacing an earlier bridge in wood, a material that was very abundant in the region. The collapse of this structure must have occurred by the Middle Ages, since the medieval timber replacement can be dated in all likelihood to the first half of the fourteenth century. It would seem to date from between 1314, when Count Heinrich of Tyrol commissioned the entrepreneur H. Kunter by contract to open an Eisack valley trail, the Kuntersweg, and 1390, when a document includes mention of construction of a bridge at Blumau.

It is notable that Galliazzo rejects the hypothesis that the structure could be the Pons Drusi which is marked on the Peutinger Diagram but in no other documentary source. He and other authors of the Südtirol archaeology volume consider the Pons Drusi to have been a bridge in the heart of Bolzano.

I took only rough notes from his bibliography and have not read these further materials, so I apologize that I must offer these references here with incomplete titles. The 1930 report at page 366 of Archivio per l'Alto Adige that first pointed to the existence of these remains should also be added to this reading list:

Dal Ri, Lorenzo. “?Title unknown.” In La Venetia nell’area padano-danubiana: le vie di comunicazione: Convegno internazionale: Papers, edited by Guido Rosada. Padova: CEDAM, 1990. See 620-621.

Galliazzo, Vittorio. I ponti romani. Vol. 1. 2 vols. Treviso: Canova, 1995. See 149, 249, 399.

———. “Ponti e Forme di Attraversamento di Corsi d’Acqua dell’Alto Adige in Età Romana.” In Archäologie der Römerzeit in Südtirol. Beiträge und Forschungen. Forschungen zur Denkmalpflege in Südtirol, edited by Lorenzo Dal Ri and S. Di Stefano, 57-71. 1, 2002. [The article quoted in this post.]

———. , ed. Via Claudia Augusta: un’arteria alle origini dell’Europa: ipotesi, problemi, prospettive : atti del Convegno internazionale Feltre 24-25 settembre 1999. Comune di Feltre, 2002. See 233, 236.

Olivi, M. “?Title unknown (‘Strada Romana Bolzano-Ponte Gardena’ or similar).” Archeologia Veneta 7 (1984). See 256-257.

Tabarelli, Gian Maria. Strade Romane nel Trentino e nell’Alto Adige. Trento: Temi Ed., 1994. See 122-125.

Regrettably, this very important structure is not yet included (at the time of this posting) in Wikipedia's List of Roman Bridges.

Spelling

Some readers do seem to care strongly about the plural spelling of stemma. Dictionaries such as the OED offer three standard meanings (the simple eye of certain insects / the record of an ancient Roman genealogy / the tree diagram showing the relationships among manuscripts of a literary work) and the standard plural spelling "stemmata." On the Macro-Typography website, stemma is being used in a fourth, novel meaning, as a term for any graphical representation of any branching inter-relationships. It is a sense that Karl-August Wirth used in an article in German reviewing four typical medieval graphic forms used in educational texts: the table, stemma, arbor and rota. This usage of stemma is preferable to "tree." The objections to tree are that the word is misleading, especially because it is loaded in favour of twig-like graphic patterns, but also because it has generated a long history of confusion about that figure's "correct" orientation. A broader term would be useful. But is "stemma" in this sense ready for prime time? With a plural that is drawn from Greek, stemma is bound to remain a term of scientific and scholarly jargon. Diagram, also of Greek origin, would not be a term in international standard English if its plural were still "diagramata". We need to anglicize stemma with a regular English plural, "stemmas", if we hope to bring the term into wider currency. The spelling "stemmata" will remain in place on the Macro-Typography website, because the audience there is mainly of historians, but expect the anglicized plural "stemmas" for wider audiences interested only in graphic design.