Thayer's Note: Stevenson's "translation" of Ptolemy, to which this page belongs, is abysmally bad. It should not be used for any serious purpose. For details and correctives, see my Ptolemy homepage.
My notes on the map: No information has been added to Ptolemy's text as I have it, so there is almost no topographic data; the courses of the rivers also remain unmapped.
The interesting item is of course one of Ptolemy's biggest mistakes: Scotland is rotated clockwise by about 90°. The error occurs at a very specific place, which I've marked by a red line on the map, extending from the Solway Firth to Newcastle. No coincidence at all that this is almost exactly the line of Hadrian's Wall: all of a sudden the Roman geographer loses all his land data and has to rely on pilot's accounts, with choppy seas and strong currents accounting for the bad data. Ptolemy may well have had only a single report for the navigation of the top of Scotland; what else could he do? (For an alternative and vaguer explanation — I'm not in the least convinced by my own — see John Ward's The Roman Era in Britain, p14; for yet another explanation, far more convincing and detailed, see Thomas G. Ikins' Roman Map of Britain. There are, out there, many other diagnoses of this error by Ptolemy and of his other errors, limited only by human ingenuity expressed in shelves full of books and a passel of webpages. None of them is to be trusted, probably.)
This map, when examined together with Ptolemy's maps of Belgica and Cimbria (now the Low Countries and Denmark), reveals something important about the sources of error in the Geography. In Book II, Chapter 8 we see the Dutch coast correctly placed; navigation thence along the coast ought to have showed Denmark to be, in terms of absolute coördinates within his own system, where Ptolemy puts northern Scotland, and the positions on the map of Britain would have been provided with cross-checks.
What happened instead is that in Book II, Chapter 10 we do indeed see Denmark: similarly tilted by a same large clockwise angle. I haven't yet figured them exactly, but Ptolemy's distances from Scotland to Denmark appear to be roughly the same as ours. He did his cross-checks all right, but both Scotland and Denmark were beyond the pale of Roman dominion. He is relying on sea data.
To me this suggests that Ptolemy kept two sets of data, obtained by land and by sea; that he cross-checked each internally; that he favored the land data because he knew they were more accurate; and that for the sea data he knew they weren't good, but at least he made them consistent. But once again, don't believe anything you read about Ptolemy, not even my own stuff — it's all theories and smoke.
A description of the northern coast, above which is the Duecaledonius ocean.
|Novantarum peninsula, and promontory of the same name||21*00||61°40|
|mouth of the Longus river||24*30||60°40|
|mouth of the Itis river||27*00||60°40|
|mouth of the Navarus river||30*00||60°30|
|Tarvedum or Orcas promontory||31*20||60°15|
Description of the west a side which borders on the Hibernian ocean and the Vergionius ocean.
|From the Novantian promontory||21*00||61°40|
|mouth of the Abravannus river||19*20||61°00|
|mouth of the Devas river||18*00||60°00|
|mouth of the Novius river||18*20||59°30|
|Setantiorum harbor b||17*20||57°45|
|Caeanganorum promontory||15*00||57°00 c|
|mouth of the Toesobis river||15*40||56°20|
|mouth of the Stuccia river||15*20||55°30|
|mouth of the Tuerobis river||15*00||55°00|
|mouth of the Tobius river||15*30||54°30|
|mouth of the Ratostabius river||16*30||54°30|
|Antivestaeum or Bolerium promontory||11*30||52°30|
|Damnonium or Ocrium promontory||12*00||51°30|
Description of the south side below which is the Britannic ocean. After the Ocrium promontory is
|the mouth of the Cenio river||14*51 d||51°45|
|mouth of the Tamarus river||15*40||52°10|
|mouth of the Iscas river||17*40||52°20|
|mouth of the Alaunus river||17*40||52°40|
|mouth of the Trisantonis river||20*20||53°00|
A description of the eastern and the southern side next to which is the Germanic ocean. After the Tarvedum promontory, or Orcades, by which it is known,
|mouth of the Ila river||30*00||59°40|
|a high shore||29*00||59°40|
|Varar estuary||28*00 e||59°40|
|mouth of the Loxa river||27*30||59°40|
|mouth of the Caelis river||27*00||58°45|
|mouth of the Deva river||26*00||58°30|
|mouth of the Tina river||24*00||58°30|
|mouth of the Alaunus river||21*20||58°30|
|mouth of the Vedra river||20*10||58°30|
|Gabrantuicorum bay with many harbors||21*00||57°00|
|mouth of the Abi river||21*00||56°30|
|mouth of the Gariennus river||20*50||55°40|
|mouth of the Sidumanis river||20*10||55°00|
|Next to this the Cantium promontory||22*00||54°00|
The Novantae dwell on the side toward the north below the peninsula of this name, among whom are the following towns:
Below are the Selgovae, among whom are the following towns:
From these toward the east, but more northerly, are the Damnoni, among whom are the following towns:
Further south are the Otalini, among whom are the following towns:
Next to the Damnoni, but more toward the east near the Epidium promontory are the Epidi and next to these the Cerones; then the Carnonacae, and the Caereni but more toward the east; and in the extreme east dwell the Cornavi; from the Lemannonis bay as far as the Varar estuary are the Caledoni, and above these is the Caledonian forest, from which toward the east are the Decantae, and next to these the Lugi extending to the Cornavi boundary, and above the Lugi are the Smertae; below Caledonia are the Vacomagi, among whom are the following towns:
Below these toward the west are the Venicones, whose town is
More toward the east are the Taezali
Below the Selgovae and Otalini f are the Brigantes extending to both seas, among whom are the following towns:
|Eboracum, Legio VI Victrix||20*00||57°20|
Near which on the Opportunum bay are the Parisi and the town
Below these are the Brigantes but some distance toward the west are the Ordovices, among whom are the towns:
From these toward the east are the Cornavi, among whom are the towns:
Next to these are the Coritani, among whom are the towns:
Next are the Catuvellauni, among whom are the towns:
Next to these are the Iceni,
Farther eastward and near the estuary of the Tamesa are the Trinovantes
Below the peoples we have mentioned, but more toward the west are the Demetae, whose towns are:
More toward the east are the Silures
Next to these are the Dobuni,
then the Atrebati
Next to these, but farther eastward, are the Canti among whom are the towns:
Below the Atrebati and the Canti are the Regni and the town
Below the Dobuni are the Belgae and the towns:
Toward the west and south of these are the Durotriges whose town is
Next to these, but more to the west, are the Dumnoni, whose towns are:
|Isca, where is located Legio II Augusta||17*30||52°45|
The islands which are near Albion island and the Orcades promontory are:
Above these islands are the Orcades, about thirty in number,
|the middle of which is in||30*00||61°40|
Far above these is the island Thule.
|The part of this which extends much toward the west is in||29*00||63°00|
|that which is farthest eastward is||31*40||63°00|
|that which is farthest northward is||30*20||63°15|
|that which is farthest southward is||30*20||62°40|
|the middle is in||30*20||63°00|
Eastward from the Trinovantes region there are two islands:
Below Magnus Portus is the island Vectis,
a Here, the 1932 edition has east; whether this is due to the manuscript(s) of Ptolemy or to modern carelessness, it is an egregious error and I have corrected it.
b Here is Karl Müller's apparatus:
Σεταντίων] Σετανίων ΔΧ, sed Σεταντίων D in tabula; Σεγαντίων BL2N2ΣΖΩד, Γεσαντίων E.
ιζ´ γ´´] ιζ´ γο´´ ΔΧ, 17½ arg.; 17½, al. 17‑1/3 cod. 4803.
νζ´ δ´´] νζ´ CW, νζ´ γ´´ δ´´ EZ.
Portus 300 stadia a Morecambe bay dissitus, non ponendus ad Layne fl. et Lancaster (Longoricum in Not. Dign., ut vid.) oppidum, ut nonnullis placuit, sed ad Ribble fl. et Preston opp., uti recte monuit Horslejus in Brit. Rom. In Geogr. Rav. 5, 31, p438, oppida hujus regionis afferuntur: Seguntio (h. Caer Siont), Canubio (Conovium Itin., hod. Convey), Mediolano, Saudonia, Deva (h. Chester), ex quibus Saudonia fort. ad eos pertinet quos Ptolemaeus Setantios dicit. Nescio an conferendum sit Sextantio nomen urbis Gallicae. In populorum oppidorumque recensu Ptolemaeus neque Setantios memorat, neque Duecaledonios neque Ceangos; alium sc. fontem in hoc, alium in periplo ob oculos habuit. Ceterum quoniam Setantiorum portus sec. Ptol. a Deva (Chester) boream versus tantum fere distat, quantum ab eadem Deva urbe versus occasum recte distat Segontium oppidum (Caer Siont) Monae insulae objacens, fuere qui Σεγοντίων pro Σεταντίων legendum esse ac de situ hujus portus Ptolemaeum errasse censerent (V. Camden, p793).
c On plotting the map, I found that the modern edition's 56°00 must surely be an error, probably for 57°00 which is where the medieval map puts this peninsula. Müller, however, has νς´ in the Greek original and 56 in his Latin.
d Here, the 1932 edition has 14*51, clearly a modern error for 14*00, at which exact longitude the medieval map puts a Cemnonus fl.; and in fact Müller has 14*/51°45 so that the mistake can be ascribed to sloppy reading of the Latin in Müller: one of the many pieces of internal evidence that show that Stevenson did not work from an original text, but from Müller's Latin translation.
e On plotting the map, I found that the modern edition's 27*00 must be in error, Ptolemy's own value almost certainly being between 27*30 and 29*00 exclusive; I've emended it to 28*00 which seems to be where the medieval map puts this estuary.
g No reasonable emendation will put Petuaria on a bay; and I can't tell whose error this is, either.
in 380 AD
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