Monday, February 20, 2012

Roman Geography

Imagine a military commander setting out to launch an invasion of a territory the size of a country. He has no maps, and feels the need for none.

Imagine a mighty state that has through conquest established an empire encompassing some two and a half million square miles and held it for centuries. Its rulers have no accurate maps and have only a hazy idea where the empire's borders lie.

As Susan P. Mattern argues in her fine Rome and the Enemy: Imperial Strategy in the Principate, this was ancient Rome. In a nutshell, the Romans had virtually no maps, and none that were accurate:
Maps in the sense of two-dimensional, scaled representations of the world . . . were . . . not the familiar objects in antiquity that they are today. There was no Greek word that meant, specifically, “map,” and there appears to have been none in Latin either . . ..

The practical tools available to generals were mainly the itineraries compiled by the army; travelers could use the periploi composed by merchants, where these existed. Scaled maps were probably not used or perceived as useful for military or strategic purposes. While the argument from silence is always suspect for antiquity, it is striking that no author of any tactical treatise and no historian of antiquity including Caesar mentions maps in a military context or even, virtually at all.
As the quote indicates, the principal geographic tool that the Romans used was not a two-dimensional map but an “itinerary.” This was a list of distances between specified stops on a route. The Antonine Itinerary is the most famous example.

Itineraries could be expressed in visual form, but they lacked direction and were not “maps” as we think of them:
The most spectacular example is the Tabula Peutingeriana . . . [which] is not just a list, but a road map of the world that displays stops and distances in graphic form. . . . Roads are represented by lines, stops by jags in the lines, and distances between stops are inscribed as on modern road maps. Spas and villages are represented as symbols; the Mediterranean is a snaky green line through the middle. The length of the Peutinger Table is more than twenty times its width, probably because it was originally drawn on a papyrus roll. Thus it illustrates the limitations of “odological” information very well: it is not possible to tell the direction of a route on this map or to gain a two-dimensional sense of the shape of any region . . ..

I encourage you to double-click on Peutinger Table, which appears just above, and try to imagine that it is your sole guide on a trip from, say, Rome to Trier, or London to Antioch.  Then, go to Omnes Viae, a wonderful site where you can plot the same trip and get results both in itinerary form and plotted out on a map.  My only regret is that the site doesn't also plot out the trip on a copy of the Peutinger Table itself.

Although there appear to have been a handful of two-dimensional maps available to the Romans, they were neither scaled nor accurate and, as noted above, it does not seem that they were consulted for military purposes. Even a quick glance at a reconstruction of the map probably best known to Romans during the Empire, the so-called Map of Agrippa (shown at the top of this post), explains why.  Assuming it existed (one scholar has argued that it was not a map, but text only), Agrippa's orbis terrarum urbi spectandus (the “world to be looked at by the city”) is known primarily from a description in Book III Pliny the Elder's Natural History:

Baeticae longitudo nunc a Castulonis oppidi fine Gadix CCL et a Murgi maritima ora XXV p. amplior, latitudo a Carteia Anam ora CCXXXIIII p. Agrippam quidem in tanta viri diligentia praeterque in hoc opere cura, cum orbem terrarum orbi spectandum propositurus esset, errasse quis credat et cum eo Divum Augustum? is namque conplexam eum porticum ex destinatione et commentariis M. Agrippae a sorore eius inchoatam peregit.

At the present day the length [i.e., east-west distance] of Bætica, from the town of Castulo, on its frontier, to Gades is 250 miles, and from Murci, which lies on the sea-coast, twenty-five miles more.  The breadth [i.e., north-south distance], measured from the coast of Carteia, is 234 miles.  Who is there that can entertain the belief that Agrippa, a man of such extraordinary diligence, and one who bestowed so much care on his subject, when he proposed to place before the eyes of the world a survey of that world, could be guilty of such a mistake as this, and that too when seconded by the late emperor the divine Augustus?  For it was that emperor who completed the Portico which had been begun by his sister, and in which the survey was to be kept, in conformity with the plan and descriptions of M. Agrippa.

(As as aside, I note that there seems to be disagreement whether the word in the Latin text is urbi or orbi - "[to be seen] by the city [of Rome]" or " by the world".  Prof. Mattern apparently believes it is urbi, the authors of the University of Chicago website the latter.)

At all events, Prof. Mattern elaborates on the Map of Agrippa as follows:
Apparently this was an image of the world painted on the Porticus Vipsania, a building funded by Augustus' close friend [Marcus Vipsanius] Agrippa in the Campus Martius, and completed after his death by Augustus. It divided the world into twenty-four regions, and may have been accompanied by a commentary, which was also published separately, [which] offered length and breadth measurements for each of the twenty-four sections.

There is substantial reason to believe the understanding of the Roman ruling class concerning world geography was generally consistent with Agrippa's Map.  "It is doubtful whether any [of the ancient geographers] . . . actually drew maps to illustrate their texts."  But reconstructions of the world based on the descriptions of the Greek geographer Strabo, who was "part of that world", show a generally similar picture:

Focusing in particular on Europe, we find the continent oddly narrowed north to south, with a flattened northern cost that leaves the Pyrenees running north-south rather than east-west, and Britain lying on its side, almost as close to Spain as it is to Gaul and extending on the east all the way to Germany.  This may explain, for example, the rather odd description of Britain that Tacitus provides in the Agricola:
Britannia, insularum quas Romana notitia complectitur maxima, spatio ac caelo in orientem Germaniae, in occidentem Hispaniae obtenditur, Gallis in meridiem etiam inspicitur; septentrionalia eius, nullis contra terris, vasto atque aperto mari pulsantur. Formam totius Britanniae Livius veterum, Fabius Rusticus recentium eloquentissimi auctores oblongae scutulae vel bipenni adsimulavere.
Britain, the largest of the islands which Roman geography includes, is so situated that it faces Germany on the east, Spain on the west; on the south it is even within sight of Gaul; its northern extremities, which have no shores opposite to them, are beaten by the waves of a vast open sea. The form of the entire country has been compared by Livy and Fabius Rusticus, the most graphic among ancient and modern historians, to an oblong shield or battle-axe.
A general on campaign would have used such a map at his peril:

It is true that later in the Principate, a somewhat more accurate description of the world became available to the Romans, in the form of Ptolemy's work:

But "antiquity did not share today's pronounced tendency to value the new over the old in scholarship."  As a result, "Ptolemy's work, which was so fundamental to Renaissance cartography had only a slight impact on later Roman geography and remained obscure until the fourteenth century."

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