The Ravenna Cosmography - The British Section

Sometime during the seventh century of this Common Era, an unknown monk in the Monastery at Ravenna on the Adriatic (eastern) coast of Italy compiled a list of all the towns and road-stations throughout the Roman Empire; this important historical document has since become known as the Ravenna Cosmography.

The best available text is that of the Codex Vaticanis (Urb. Lat. #961). We will deal only with the portion which describes the British Isles, that is, from the last paragraph of Verse 30 through to the middle of Verse 32, which is contained within just four manuscript pages. The numbers accompanying the text in the following table are those of I.A. Richmond and O.G.S. Crawford, from their article The British Section of the Ravenna Cosmography, in Archaeologia Vol.XCIII (1949) pp.1-50.

The first portion of the document is by far the largest and lists the towns of Roman Britain, in a somewhat haphazard fashion, followed by the rivers and smaller islands, again in no readily-discernable pattern. The R&C entries are; 1-227 Cities, 228-235 Wetlands, 236-271 British Rivers, 272-274 Irish Rivers, 275-302 British Islands, 303-306 ‘Islands of the Northern Ocean’.

The Codex Vaticanis manuscript pages and their constituent R&C entries are;

45v – 303-306 and 1-51.5

46r – 51.5-167.5

46v – 167.5-271

47r – 272-302

This websites’ translations of the text and any explanatory notes are [highlighted and enclosed in square brackets].

(V.30) … Iterum sunt in ipso oceano [insule] que dicuntur
[Once again, there are within the selfsame ocean (islands) which are named:]
303	Vectis	[= Vectis = Isle of Wight, Hampshire]
304	Malaca	[?= Malaius* = Island of Mull, Inner Hebrides?] [Possible Duplicate! See R&C.298]*
305	Insenos	[?= Hibernia* = Ireland?]*
306	Taniatide	[= Tanatvs = Isle of Thanet, Kent]
(V.31) In oceano vero occidentale est insula quae dicitur Britania, ubi olim gens Saxonum veniens ab antiqua Saxonia cum principe suo Ansehis modo havitare videtur; quamvis insulam, ut diximus, quidam Grecorum phylosophi quasi [i]micosmin appellaverunt; nam nos tam magnam insulam neque in supra scripto Mari Magno neque in praefato oceano dilatissimo neque in quo praediximus sino oceani legendam nullo modo reperimus. In qua Britania plurimas fuisse legimus civitates [et castra], ex quibus aliquantas designare volumus, id est:
translation
1	Giano	[unknown]
2	Eltabo	[unknown]
3	Elconio	[unknown]
4	Nemetotacio	[?= Nemetostatio = North Tawton, Devon?]
5	Tamaris	[?= Tamaris = Plymouth, Devon?]
6	Purocoronauis	[?= Dvrocornavivm = Carn Brea, Cornwall?]
7	Pilais	[unknown]
8	Vernalis	[unknown]
9	Arduarauenatone	[unknown]
10	Devionisso	[unknown]
11	Statio Deventiasteno	[?= Statio Deventiasteno = Nanstallon, Cornwall?]
12	Duriarno	[unknown]
13	Uxelis	[?= Vxelis = Launceston, Cornwall?]
14	Verteuia	[unknown]
15	Melamoni	[unknown]
16	Scadu namorum	[= Isca Dvmnoniorvm = Exeter, Devon]
17	Termonin	[unknown]
18	Mestevia	[unknown]
19	Milidunum	[unknown]
20	Apaunaris	[unknown]
21	Masona	[unknown]
22	Alovergium	[unknown]
Iterum iuxta supscriptam civitatem Scadoniorum est civitas quae dicitur
[Once again, beside the Dumnonian* towns listed above are (other) towns which are named:]*
23	Moriduno	[unknown]
24	Alauna silua	[unknown]
25	Omiretedertis	[unknown]
26	Lindinis	[= Lindinis = Ilchester, Somerset]
27	Canza	[unknown]
28	Dolocindo	[?= Durocendum* = Chew Stoke, Avon?]*
29	Clauimo	[?= Clavsentvm = Bitterne, Hampshire?]
30	Morionio	[unknown]
31	Boluelaunio	[unknown]
32	Alauna	[unknown]
33	Coloneas	[unknown]
34	Aranus	[unknown]
35	Anicetis	[?= Aqvae Svlis = Bath, Avon?]
36	Melezo	[unknown]
37	Ibernio	[?= Ivernium* = Iwerne, Dorset?]*
38	Bindogladia	[= Vindocladia = Badbury Rings, Dorset]
39	Noviomagno	[?= Lake Farm, Dorset?]
40	Onna	[unknown]
41	Venta Velgarom	[= Venta Belgarvm = Winchester, Hampshire]
42	Armis	[unknown]
43	Ardaoneon	[?= [portvs] Ardaoni = Portchester, Hampshire?]
44	Navimago Regentium	[= Noviomagvs Regnorvm = Chichester, Sussex]
45	Leuco magno	[= Levcomagvs = East Anton, Hampshire]
46	Cunetzone	[= Cvnetio = Mildenhall, Wiltshire]
47	Punctuobice	[?= Pontes = Staines, Surrey?]
48	Ventaslurum	[= Venta Silvrvm = Caerwent, Gwent]
49	Iupania	[unknown]
50	Metambala	[unknown]
51	Albinumno	[unknown]
52	Isca Augusta	[= Isca Silvrvm = Caerleon, Gwent]
53	Bannio	[= Gobannivm = Abergavenny, Gwent]
54	Bremia	[= Bremia = Llanio, Dyfed]
55	Alabum	[?= Alabvm = Llandovery, Dyfed?]
56	Cicutio	[?= Cicvcivm = Y-Gaer, Powys?]
57	Magnis	[= Magnis = Kenchester, Hereford & Worcester]
58	Brano.Genium	[= Bravonivm = Leintwardine, Hereford & Worcester]
59	Epocessa	[unknown]
60	Ypocessa	[unknown]
61	Macatonion	[?= Moridvnvm = Carmarthen, Dyfed?]
62	Glebon colonia	[= Glevvm Colonia = Gloucester, Gloucestershire]
63	Argistillum	[?= Ariconivm = Weston-under-Penyard, Hereford & Worcester?]
64	Vertis	[= Vertis = Worcester, Hereford & Worcester]
65	Salinis	[= Salinae = Droitwich Spa, Hereford & Worcester]
66	Cironium Dobunorum	[= Corinivm Dobvnnorvm = Cirencester, Gloucestershire]
67	Iacio Dulma	[?= Lactodvrvm = Towcester, Northamptonshire?] [This entry is replicated; see R&C.95]
68	Anderelio Nuba	[?= Anderitvm Nova? = Pevensey, Sussex]
69	Mutuantonis	[unknown]
70	Lemanis	[= Portvs Lemanis = Lympne, Kent]
71	Dubris	[= Portvs Dvbris = Dover, Kent]
72	Duro auerno Cantiacorum	[= Dvrovernvm Cantiacorvm = Canterbury, Kent]
73	Rutupis	[= Rvtvpiae = Richborough, Kent]
74	Durobrabis	[= Dvrobrivae = Rochester, Kent]
75	Landini	[unknown]
76	Tamese	[unknown]
77	Brinauis	[unknown]
78	Alauna	[unknown]
79	Utriconion Cornoviorum	[= Viroconivm Cornoviorvm = Wroxeter, Shropshire]
80	Lavobrinta	[= Levobrinta = Forden Gaer, Powys]
81	Mediomanum	[?= Mediomanvm = Caersws, Powys?]
82	Seguntio	[= Segontivm = Caernarfon, Gwynedd]
83	Canubio	[= Canovivm = Caerhun, Gwynedd]
84	Mediolano	[= Mediolanvm = Whitchurch, Shropshire]
85	Saudonio	[unknown]
86	Deva victris	[= Deva Victrix = Chester, Cheshire]
87	Veratino	[unknown]
88	Lutudaron	[= Lvtvdarvm = Crich, Derbyshire]
89	Derbentione	[= Derventio = Littlechester, Derbyshire]
90	Salinis	[= Salinae = Middlewich, Cheshire]
91	Condate	[= Condate = Northwich, Cheshire]
92	Rate Corion	[= Ratae Corioneltavorvm = Leicester, Leicestershire]
93	Eltauori	[see entry above]
94	Lectoceto	[= Letocetvm = Wall, Staffordshire]
95	Iacio Dulma	[?= Lactodvrvm = Towcester, Northamptonshire?] [This entry is replicated; see R&C.67]
96	Virolanium	[= Vervlamivm = St. Albans, Hertfordshire]
97	Londinium Augusti	[= Londinivm Avgvsta = London, Greater London]
98	Cesaromago	[= Caesaromagus* = Chelmsford, Essex]*
99	Manulodulo. colonia	[= Camvlodvnvm Colonia = Colchester, Essex]
100	Durcinate	[?= Dvrolitvm = Nr. Romford, Gtr. London?]
101	Duro viguto	[= Dvrovigvtvm = Godmanchester, Cambridgeshire]
102	Durobrisin	[= Dvrobrivae = Water Newton, Cambridgeshire]
103	Venta Cenomum	[= Venta Icenorum* = Caistor St. Edmund, Norfolk]*
104	Lindum Colonia	[= Lindvm Colonia = Lincoln, Lincolnshire]
105	Bannovallum	[= Bannovalvm = Horncastle, Lincolnshire]
106	Nauione	[= Navio = Brough, Derbyshire]
107	Aquis Arnemeza	[= Aqvae Arnemetiae = Buxton, Derbyshire]
108	Zerdotalia	[?= Ardotalia = Melandra Castle, Derbyshire?]
109	Mantio	[= Mamvcivm = Manchester, Greater Manchester]
110	Alunna	[= Alavana = Watercrook, Lancashire]
111	Camulodono	[?= Cambodvnvm = Slack, West Yorkshire?]
112	Calunio	[?= Calunium? = Lancaster, Lancashire?]
113	Gallunio	[?= Galava = Ambleside, Cumbria?]
114	Medibogdo	[= Mediobogdvm = Hardknot, Cumbria]
115	Cantiventi	[= Glannoventa = Ravenglass, Cumbria]
116	Iuliocenon	[?= Tvnnocelvm = Beckermet, Calder Bridge, Cumbria?]
117	Gabrocentio	[= Gabrosentvm = Moresby, Cumbria]
118	Alauna	[= = Maryport, Cumbria]
119	Bribra	[= Bibra = Beckfoot, Cumbria]
120	Maio	[= Maglona = Old Carlisle, Cumbria]
121	Olerica	[see entry above]
122	Derventione	[= Derventio = Papcastle, Cumbria]
123	Ravonia	[= Bravoniacvm = Kirkby Thore, Cumbria]
124	Bresnetenaci Veteranorum	[= Bremetenacvm Veteranorvm = Ribchester, Lancashire]
125	Pampocalia	[unknown]
126	Lagentium	[= Lagentivm = Castleford, West Yorkshire]
127	Valteris	[= Verteris = Brough, Cumbria]
128	Bereda	[= Voreda = Old Penrith, Cumbria]
129	Lagubalumi	[= [link_post post_id="458"] = Carlisle, Cumbria]
130	Magnis	[= Magnis = Carvoran, Northumberland]
131	Gabaglanda	[?= Camboglanna = Birdoswald, Cumbria?] [Possible duplicate! See R&C.167]
132	Vindolande	[= Vindolanda = Chesterholm, Northumberland]
133	Lineoiugla	[= Longovicivm = Lanchester, Durham]
134	Vinovia	[= Vinovivm = Binchester, Durham]
135	Lavaris	[= Lavatris = Bowes, Durham]
136	Cactabactonion	[= Cataractonivm = Catterick, North Yorkshire]
137	Eburacum	[= Ebvracvm = York, North Yorkshire]
138	Decuaria	[= Petvaria = Brough on Humber, Humberside]
139	Devovicia	[?= Delgovicia = nr. Millington, Humberside?]
140	Dixio Lugunduno	[?= Dictivm = Whitby, North Yorkshire?] [?Lugundunum, unknown?]
141	Coganges	[= Concangis = Chester-le-Street, Durham]
142	Corie Lopocarium	[= Corstopitvm = Corbridge, Northumberland] [?Lopocarium, unknown?]
143	Serduno	[= Segedvnvm = Wallsend, Tyne & Wear]
144	Condecor	[= Condercvm = Benwell, Tyne & Wear]
145	Vindovala	[= Vindobala = Rudchester, Northumberland]
146	Onno	[= Onnvm = Halton Chesters, Northumberland]
147	Celunno	[= Cilvrnvm = Chesters, Northumberland]
148	Brocoliti	[= Brocolitia = Carrawburgh, Northumberland]
149	Velurtion	[= Vercovicivm = Housesteads, Northumberland]
150	Esica	[= Aesica = Great Chesters, Northumberland]
151	Banna	[?= Banna = Castlesteads, Cumbria?]
152	Uxelludamo	[= Vxelodvnvm = Stanwix, Cumbria]
153	Avalana	[= [link_post post_id="224"]Burgh-by-Sands (Aballava) = Burgh by Sands, Cumbria]
154	Maia	[= Maia = Bowness on Solway, Cumbria]
155	Fanocodi	[?= Fanvm Cocidi = Bewcastle, Cumbria?]
156	Brocara	[= Brocavvm = Brougham, Cumbria]
157	Croucingo	[unknown]
158	Stodoion	[unknown]
159	Sinetriadum	[unknown]
160	Clindum	[unknown]
161	Carbantium	[unknown]	.
162	Tadoriton	[unknown]
163	Maporiton	[unknown]
164	Alitacenon	[unknown]
165	Loxa	[unknown]
166	Locatreve	[unknown]
167	Cambroianna	[?= Camboglanna = Birdoswald, Cumbria] [Possible duplicate! See R&C.131]
168	Smetri	[unknown]
169	Uxela	[unknown]
170	Lucotion	[unknown]
171	Corda	[unknown]
172	Camulosessa	[unknown]
173	Presidium	[unknown]
174	Brigomono	[unknown]
175	Abisson	[unknown]
176	Ebio	[unknown]
177	Coritiotar	[unknown]
178	Celovion	[unknown]
179	Itucodon	[unknown]
180	Maromago	[unknown]
181	Duabsisis	[unknown]
182	Venutio	[unknown]
183	Trimuntium	[= Trimontivm = Newstead, Borders]
184	Eburo caslum	[?= Habitancvm = Risingham, Northumberland?]
185	Bremenium	[= Bremenivm = High Rochester, Northumberland]
186	Coccimeda	[unknown]
187	Alauna	[?= Alavna = Learchild, Northumberland?]
188	Oleiclavis	[unknown]
189	Evidensca	[unknown]
190	Rumabo	[unknown]
Iterum sunt civitates in ipsa Britainia recto tramite una alteri conexa, ubi et ipsa Britania plus angustissima de oceano in oceano esse dinoscitur, id est
[Here are listed the stations within the said Island joined together along a straight track where Britain is at its very thinnest from ocean to ocean, they are named:]
191	Velunia	[= Velvniate = Carriden, Central]
192	Volitanio	[? = Mumrills]
193	Pexa	[?= Castlecary]
194	Begesse	[?= Bar Hill]
195	Colanica	[?= Auchendavy]
196	Medio Nemeton	[?= Cadder]
197	Subdobiadon	[?=Balmuildy]
198	Litana	[?=Bearsden]
199	Cibra	[?=Castlehill]
200	Credigone	[?=Old Kilpatrick]
Iterum est civitas quae dicitur
[Also (there are) cities which have been designated:]
201	Iano	[unknown]
202	Maulion	[unknown]
203	Demerosesa	[unknown]
204	Cindocellum	[unknown]
205	Cerma	[unknown]
206	Veromo	[unknown]
207	Matovion	[unknown]
208	Ugrulentum	[unknown]
209	Rauatonium	[unknown]
210	Iberran	[unknown]
211	Pinnatis	[?= [castra] Alata = Inchtuthil, Tayside?]
212	Tuessis	[unknown]
213	Lodone	[unknown]
214	Litinomago	[unknown]
215	Devoni	[?= Devana = Aberdeen, Grampian?]
216	Memanturum	[unknown]
217	Decha	[unknown]
218	Bograndium	[unknown]
219	Ugueste	[unknown]
220	Leuiodanum	[unknown]
221	Poreo Classis	[?= Horrea Classis = Carpow, Fife?]
222	Levioxaua	[unknown]
223	Cermium	[unknown]
224	Victorie	[unknown]
225	Marcotaxon	[unknown]
226	Tagea	[unknown]
227	Voran	[unknown]
Sunt autem in ipsa Britania diversa loca, ex quibus aliquanta nominare volumus, id est
[In Britain there are, however, certain places for which the number of names are many, they are:]
228	Maponi	[unknown]
229	Mixa	[unknown]
230	Panovius	[?= Devona* = Don, Grampian?]*
231	Minox	[unknown]
232	Taba	[= Tava* = Tay, Tayside]*
233	Manavi	[unknown]
234	Segloes	[?= Segelocvm = Littleborough/River Trent, Nottinghamshire?]
235	Daunoni	[?= Danvm = Doncaster/River Don, South Yorkshire?]
Currunt autem per ipsam Britaniam plurima flumina, ex quibus aliquanta nominare volumus, id est
[Many rivers are running throughout Britain, for which the number of names are many, they are:]
236	Traxula	[?= Test, Hampshire?]
237	Axium	[?= Itchen, Hampshire?]
238	Maina	[?= Meon, Hampshire?]
239	Sarua	[= Sabrina* = Severn, Gloucestershire]*
240	Tamaris	[= Tamaris* = Tamar, Cornwall/Devon]*
241	Naurum	[unknown]
242	Abona	[= Abona* = Avon, Avon]*
243	Isca	[= Isca* = Usk, Gwent]*
244	Tamion	[?= Taff, Glamorgan?]
245	Auentio	[= Aventio* = Ewenny, Glamorgan]*
246	Leuca	[= Leuca* = Loughor, Dyfed/Glamorgan]*
247	Iuctius	[= Stuctia* = Ystwyth, Dyfed]*
248	Leugosena	[= Seteia* = Mersey, Merseyside]*
249	Coantia	[?= Kent, Cumbria?]
250	Doruantium	[= Derventio* = Derwent, Cumbria]*
251	Anaua	[= Anava* = Annan, Dumfries & Galloway]*
252	Bdora	[?= Eden, Cumbria?]
253	Nouitia	[= Novius* = Nith, Dumfries & Galloway]*
254	Adron	[?= Ayr, Strathclyde?]
255	Certisnassa	[unknown]
256	Intraum	[unknown]
257	Antrum	[unknown]
258	Tinoa	[= Tinea* = Tyne, Tyne & Wear]*
259	Liar	[unknown]
260	Lenda	[unknown]
261	Vividin	[unknown]
262	Durolavi	[unknown]
263	Alauna	[= Alaunus* = Aln, Northumberland]*
264	Coguueusuron:	[?= Cogus* = Coquet, Northumberland?] [?= Vensuron = Wansbeck, Northumberland?]*
265	Durbis	[?= Dour, Kent?]
266	Lemana	[?= Rother, East Sussex/Kent?]
267	Novia	[?= Novius* = Pevensey, Sussex?]*
268	Raxtomessa	[= Rex Tamesis* = Thames, Essex/Kent]*
269	Senua	[unknown]
270	Cunia	[unknown]
271	Velox	[unknown]
(V.32) Iterum in eodem oceano occidentali, post ipsam magnam Britaniam, simulque et amplius longius, ut diximus, quam omnes insule e terra magna finita [ex] parte septentrionali, magis ex ipsa occidentali, est insula maxima quae dicitur Ibernia, que, ut dictum est, et Scotia appellatur. cuius post terga, ut iam praemisimus, nullo modo apud homines terra invenitur.
translation
272	Etsodisinam:	[?= Elsodus* = unknown?] [?= Sinam = Shannon, Ireland?]*
273	Cled	[unknown]
274	Terdec	[unknown]
Iterum in ipso oceano occidentali ponuntur diverse insule, ex quibus aliquantas nominare volumus, id est
[Also, in this selfsame western ocean are planted many islands, for which the number of names are many; they are:]
275	Corsula	[unknown]
276	Mona	[= Mona = Anglesey, Gwynedd]
277	Regaina	[unknown]
278	Minerve	[= Manavia* = Isle of Man]*
279	Cunis	[unknown]
280	Manna	[?= Arran, Strathclyde?]
281	Botis	[= Botis* = Bute, Strathclyde]*
282	Vinion	[unknown]
283	Saponis	[unknown]
284	Susura	[unknown]
285	Birila	[unknown]
286	Elaviana	[unknown]
287	Sobrica	[unknown]
288	Scetis	[= Scitis* = Skye, Inner Hebrides]*
289	Linnonsa	[unknown]
Item ad aliam partem dicitur insula
[Also, in other parts there are islands named:]
290	Magantia	[unknown]
291	Anas	[unknown]
292	Cana	[= Cana* = Canna, Inner Hebrides]*
293	Atina	[unknown]
294	Elete	[?= Islay, Inner Hebrides?]
295	Daroecla	[?= Jura, Inner Hebrides?]
296	Esse	[unknown]
297	Gradena	[unknown]
298	Maiona	[?= Malaius = Mull, Inner Hebrides?] [Possible Duplicate! See R&C.304]
299	Longis	[?= Lewis, Outer Hebrides?]
300	Eirimon	[?= Harris, Outer Hebrides?]
301	Exosades	[?= Uist, Outer Hebrides?]
ubi et gemme nascuntur, [sicut] legimus. Item in ipso oceano numero insule triginta tres quae et
translation
302	Dorcades	[= Orcades* = Orkney Islands]*
appellantur, que quamvis non existant omnes exculte, attamen nomina illarum volueramus Christo nobis iuvante designare; sed quia peccatis emergentibus suete a diversis gentibus ipsa dominatur patria et, ut barbarus mos est, varie vocationes easdem insulas appellant, ideo earum reliquimus nomina designandum.
translation pending

Places Named on the Ravenna Map

Ravenna Spelling	Accepted Spelling	Associated Modern Place-Name
Serduno	Segedvnvm	Wallsend, Tyne & Wear
Condecor	Condercvm	Benwell, Tyne & Wear
Vindovala	Vindobala	Rudchester, Northumberland
Onno	Onnvm	Halton Chesters, Northumberland
Celunno	Cilvrnvm	Chesters, Northumberland
Brocoliti	Brocolitia	Carrawburgh, Northumberland
Velurtion	Vercovicivm	Housesteads, Northumberland
Esica	Aesica	Great Chesters, Northumberland
Banna	Banna	Castlesteads, Cumbria
Uxelludamo	Vxelodvnvm	Stanwix, Cumbria
Avalava	Burgh-by-Sands (Aballava)	Burgh by Sands, Cumbria
Maia	Maia	Bowness on Solway, Cumbria
Fanocodi	Fanvm Cocidi	Bewcastle,
Vindolande	Vindolanda	Chesterholm, Northumberland
Magnis	Magnis	Carvoran, Northumberland
Gabaglanda	Camboglanna	Birdoswald, Cumbria
Bibra	Bibra	Beckfoot, Cumbria
Alauna		Maryport, Cumbria
Gabrocentio	Gabrosentvm	Moresby, Cumbria
Juliocenon	Tvnnocelvm	Nr. Beckermet, Calder Bridge, Cumbria
Bremenium	Bremenivm	High Rochester, Northumberland

Notable Omissions and Other Strangeness

The first twelve places are all forts on the Wall, listed from east to west, but with two notable omissions; Pons Aelivs (Newcastle upon Tyne), the original eastern terminus of the Wall, which should be listed between Segedunum and Condercum, and Concavata (Drumburgh, Cumbria), is missing from between Maia and Aballava (this is also the case on the Rudge Cup). Camboglanna is also not included among the Wall forts, but appears in the [link_post post_id="9634" type="link"]Stanegate list.

Following the forward-positioned fort at Fanum Cocidi, the list continues with the older forts along the Stanegate, where there are two more notable omissions; Corstopitvm (Corbridge, Tyne & Wear) and (Carlisle, Cumbria). In addition, Camboglanna is placed here among the forts on the [link_post post_id="9634" type="link"]Stanegate, whereas it should be included among the forts on the Wall itself.

After the controversial Gabaglanda entry, there follows the names of three forts which belong to the Western Sea Defences beyond Maia at the western terminus of the Wall itself. Next comes the inidentified Ivliocenon entry, another, otherwise unknown fort in the Western Sea Defences.

The list is completed by another forward-positioned fort, Bremenium on Dere Street, though Habitancum which lies on this same road between Bremenium and Onnum on the Wall, is anomalously omitted.

Names For the Antonine Forts

Ravenna Cosmography mentions the ten names of forts “joined together along a straight track where Britain is at its very thinnest from ocean to ocean. Can these refer to Antonine Forts? Unfortunately we know of 19 forts on the Wall rather than 10.

The Two Acre Theory – Breeze, D. J argues that the Roman names could refer only to forts in excess of 2 acres in size (including eliminating forts beyond the Wall plus Falkirk and Inveravon, the dimensions of which are unknown). Applying this to the list we come to the 10 forts listed above.

References

RomanMap.com WebSite by Tom Ikins
A version of the Ravenna Cosmography world map from Lincolnshire Web – A pictorial version of the Roman map.
Britannia in the Ravenna Cosmography from the cyberhome of Keith Matthews – A superb website with much more than the Ravenna text.