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Bill Thayer

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This webpage reproduces an article in the
Classical Review
Vol. 23 (1909), pp77‑81

The text is in the public domain:
T. Rice Holmes died in 1933.

This page has been carefully proofread
and I believe it to be free of errors.
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 p77  Last Words on Portus Itius.​a

I have something to say about Portus Itius which has never been said before; and I ask all who have read my two former articles to read to the end before they decide, considering the arguments without prejudice and reserving judgement on the writer's shortcomings.

A few days before the publication of Ancient Britain, when all the sheets had been printed, I saw that there were flaws in the article on Portus Itius which formed a part of that volume. While I was revising it I felt the need of trustworthy and detailed information regarding the experiments that were made in order to ascertain the time in which the main division of Napoleon's flotilla could clear the port of Boulogne; but I failed until too late to put my hands upon the authoritative work — Captain E. Desbrière's Projets et tentatives de débarquement aux îles britanniques — in which it is contained. Serious reviewers, British, American, and Continental, who had already devoted much time to the study of Caesar's British expeditions, have pronounced that the conclusion reached in the article which deals with the question of his landing-place is definitively established;​1 but two scholars who were convinced, and one of whom was converted, by the argument have told me that the article on Portus Itius did not seem to them to achieve demonstration; and Mr. Stuart Jones in the English Historical Review has recently written in the same sense.

It will not, however, be denied by any critic who has even an elementary knowledge of seaman­ship or is willing to accept the unanimous testimony of nautical experts that the article made one contribution to knowledge: it proved that the port from which Caesar sailed in his first expedition was Boulogne.​2 It is now generally admitted that Portus Itius was either Boulogne or Wissant. If, then, Caesar sailed from the same port on both his expeditions, Portus Itius was Boulogne. The difficulty is that he did not say that on his first expedition he started from Portus Itius; and while I was at work upon the article I felt 'obstinate questionings' in regard to his having only mentioned the harbour in connexion with the second expedition. The drift of my argument was that Boulogne was in all respects more convenient as a starting-point than Wissant, and that Caesar, having had experience of the superior advantages of Boulogne in 55 B.C., would not have abandoned it the following year. But, for want of the information which I found too late, I failed to see that Boulogne, with all its superior advantages, had, for the second expedition, one drawback which may have been damning.

I will now point out the flaws in my article that may have escaped the notice of reviewers, and ask scholars to consider that one aspect of the question — the most important of all — which has hitherto been neglected.

On page 569​3 I asked 'if eight hundred ships had been beached at Wissant [during the twenty-five days for which Caesar was windbound at Portus Itius in 54 B.C.], would it not have been necessary, in order to protect them from storm-driven spring tides, to construct an enormous naval camp, the earth necessary for which did not exist?' I asked the question because, as I have shown on pages 566‑7, there was no harbour, properly so called, at Wissant except a creek formed by the mouth of the rivulet called the Rieu d'Herlan, and possibly a small anchorage partially sheltered by a shoal. The answer is that to construct a naval camp would not have been necessary if the ships could be hauled up beyond the highest high-water mark of spring tides. Supposing that the dune which extends from the  p78 'ruisseau de Guiptun,' near Tardinghem, to the 'ruisseau d'Herlan,' at Wissant, and which did not exist in the time of Caesar,​4 were bodily removed, it would not, I think, be possible now to haul up ships beyond this mark; but if we may suppose that the subsidence which has taken place since Roman times between Sangatte and Dunkirk extended to Wissant, there must in 54 B.C. have been a fringe of beach immediately below the high ground wide enough to allow eight hundred ships to remain high and dry at all states of the tide.5

On page 571, note 2, I hardly allowed sufficient weight to the fact that the author of Bellum Africanum (10, § 1) applies the name of portus to a mere anchorage, — that of Monastir (the ancient Ruspina), which is protected from northerly and westerly winds, but otherwise exposed.6

On page 584 I argued, as Desjardins had done before, that the sixty ships which Labienus built during Caesar's absence in Britain could not have been built at Wissant, where there were certainly no dockyards and whither it would have been very difficult to convey the necessary timber, whereas the material could have been carried both by road and river to Boulogne. But I over­looked a passage in Caesar (V.8, § 1) to which I had on an earlier page called attention. He tells us that he directed Labienus 'to protect the ports' (ut portus tueretur), which implies that he thought it necessary to keep more than one port under control. Assuming then that Portus Itius was Wissant, the ships were doubtless built at Boulogne.

On page 585 I showed that, according to 'seafaring men, both English and French, who have practical experience of the winds and the currents in the Channel,' 'the passage for sailing-vessels from Boulogne to the south-eastern part of Britain is, and always has been, in circumstances such as Caesar described, not only very convenient but by far the most convenient.' But Caesar had to think of the start and of the arrival as well as of the passage; and this consideration brings me to the question on which the whole controversy really turns, — could Caesar's fleet have started from Boulogne without becoming unduly scattered?

It must of course be remembered that the port of Boulogne in the time of Napoleon was less spacious and less deep than it was 2000 years ago because it had been largely silted up.​7 Still, although the map in which Desjardins​8 attempts to depict the state of the Liane in Caesar's time and represents it as navigable for sea-going ships as far as Isques — 7 kilometres from the mouth — seems approximately correct, it is of course in part conjectural. Moreover, although we know that Boulogne was from the time of Augustus the regular starting-point for ships sailing from North-eastern Gaul to Britain and the naval station of the Roman Channel Fleet, we have no information as to the largest number of ships which ever started from it at one time. There is not even direct evidence that Aulus Plautius sailed from Boulogne;​9 if he did, some of his ships may have sailed from Ambleteuse; and we do not know how many he had. All we know  p79 is that Caesar sailed from Boulogne in 55 B.C. with about 80 transports and a few galleys; and it is probable that even this comparatively small fleet was inconveniently strung out.​10 Philip Augustus is said to have assembled 1500 ships at Boulogne in 1213 for his contemplated invasion of England;​11 but the attempt was abandoned.

Captain Desbrière's researches have shown that one of the insuperable difficulties with which Napoleon had to contend was this:— it was impossible, in the most favourable circumstances, to float more than 100 vessels out of Boulogne harbour in one tide;​12 and therefore it would have been necessary for each successive relay of ships to anchor in the roadstead until the whole flotilla had cleared the harbour. But experience proved that it was dangerous to keep more ships in the roadstead than would be able, in case an unfavourable wind sprang up, to return for shelter into the estuary; and that westerly and south-westerly winds, which were favorite for the voyage, generally made the roadstead unsafe.​13 Owing to the rapidity of the current vessels could not safely begin to move out of the port until half-an‑hour before high tide; and even those which were rowed could not continue the operation later than two hours after the tide began to fail, and then only if the wind was not against them.14

My point then is this. Although we know that the estuary of the Liane was larger and deeper in Caesar's time than in Napoleon's, we cannot be sure that Caesar would have been able to get eight times as many ships out of it in one tide as Napoleon;​15 and we know that even if he could have done so, they would have been obliged to anchor in the roadstead as they emerged until the whole flotilla had cleared the harbour. For, in the most favourable circumstances, and assuming that the harbour was as extensive and as deep as Desjardins maintained, this operation would have required not much less than ten hours:​16 if the ships had sailed on as they emerged from the estuary, the leading division would have been off the British coast at daybreak​17 before the rearmost had begun their voyage; and it is clear from Caesar's words that the start was virtually simultaneous.​18 But there is another point to mark. I have said that the ships, as they came out of the harbour, would have been obliged to anchor in the roadstead. Probably they would have been attached by hawsers to the shore, and anchored as well. For Caesar describes his start by the words naves solvit.​19 Now, as Professor J. S. Reid has written me, 'the natural meaning of the expression [navem solvere] is . . . to free the ship from all her fastenings'; and it commonly connotes the operation of unmooring, — letting go a hawser and putting off from shore or quay. Perhaps, if the ships were merely riding at anchor, the expression might, as Professor Reid admits, 'be loosely  p80 extended to lifting the anchor'; but it is very unlikely that Caesar uses it in this sense, for he repeatedly describes the operation of weighing anchor by the words sublatis ancoris.​20 It may therefore be safely concluded that if Portus Itius was Boulogne, the ships, as they passed out of the harbour, were moored alongshore outside until the signal was given for the whole fleet to set sail. Now, however closely they may have been moored, we can hardly allow a less breadth of front for each than 7 yards.​21 The ships then would have extended in a row more than 5600 yards long, — about 5 kilometres, or more than 3 miles; in other words, they would have reached from the mouth of the Liane two-thirds of the way to Ambleteuse! Does this agree with the datum that they sailed from Portus Itius?

The danger of anchoring or of mooring alongshore would of course have been increased if the operation of clearing the harbour had required more than one tide. North-westerly winds had been blowing for twenty-five days before Caesar sailed from Portus Itius; and when the wind backed to the south-west it would have been most important to seize the opportunity of sailing while it lasted. By making Wissant the starting-point this advantage would have been secured; and, although it would not have been possible to make as good a run to Britain before a south-west wind from Wissant as from Boulogne, although the labour of hauling up and hauling down the ships at Wissant would have been great, these disadvantages may not have been considered too high a price to pay for the advantages of security, certainty, and a simultaneous start.

Professor Camille Julian, of the Institut and Collège de France, who has seen the rough draft of this paper, writes to me, 'Je ne vois pas en faveur de Wissant que le nombre donné par César, et je me demande si le pays est assez peuplé, assez fertile, assez près de bonnes routes pour nourrir une armée de 10 [read 8] légions.' I would remind my friend that even if the number of ships given by Caesar — 'more than 800' — is not correct (and there is surely no reason to question it), they must have been several times as numerous as the hundred or so which had sufficed in the previous year; for they were evidently much smaller, they had to carry five legions and 2000 cavalry instead of two legions, and they included 'private vessels.' The other considerations which my friend adduces were emphasized in my article. But the comparative infertility of the country, its sparse population, and its want of good roads would not have been fatal if it was possible, as it surely was, to provision the army for a few weeks by sea or by pack-horses, which could have moved on tracks that would have been impracticable for wagons.

One may imagine that if Caesar could have foreseen the complaints that have been so often made as to the insufficiency of the data which the Commentaries contain for determining this question, he would have said: 'Your criticisms are hasty. Exercise your intelligence and inform yourselves, and you will find that I have told you enough. When I said that I chose the shortest passage and that the distance from Portus Itius to Britain was about 30 miles I made it clear that Portus Itius was either Boulogne or Wissant; and on that point you are now agreed. My account of the adventures of my cavalry transports was sufficient to show those of you who understood seaman­ship that they sailed not from Sangatte or from Wissant but from Ambleteuse, and consequently that on my first expedition I sailed from Boulogne. I did so because Boulogne was the port from which  p81 most Gallic trading vessels regularly sailed, and was, in the circumstances, the most convenient starting-point: my ships were too large to be hauled up on a beach out of the reach of spring tides, and, being comparatively few, they could clear the harbour in a single tide. Nevertheless, they were unavoidably strung out, and I had to wait several hours off the Kentish cliffs before the stragglers arrived. The fact that I made no mention of Portus Itius except in connexion with my second expedition naturally suggested to some of you that I did not sail from it on my first. That clue you ought to have followed. If you assumed that because Boulogne possessed many advantages over Wissant, it possessed that advantage which, on my second expedition, was indispensable; if you failed to reflect that I could not have got my eight hundred ships out of Boulogne harbour without their being dispersed, you cannot blame me. As I told you, I designed my new vessels expressly in order to enable them to be hauled up on dry land: I sailed from Wissant on my second expedition because from Wissant alone was it possible for them to start simultaneously; and if Wissant was not used by my successors, it was because their circumstances were wholly different from mine.'

I have allowed myself to make this flight of fancy because I wished to give prominence to the claim of Wissant. But it is enough to have shown that the case for Boulogne cannot be regarded as proved, because, if there is only one really strong argument for Wissant, that argument is so strong that it cannot be set aside. I have stated the reasons which led me to revise my opinion; and the reader now has at his disposal all the data necessary to enable him to form his own.

May I suggest that an attempt should be made to determine the question by excavation?​22 I am not sure whether the ground on which Caesar would have encamped if he had sailed from Wissant is undisturbed; but I venture to express the hope that, if excavation is practicable, MM. Salomon Reinach and Camille Jullian will make the necessary arrangements and invite subscriptions. I would gladly contribute what I can afford.

T. Rice Holmes.

[Note. — On pages 586‑7 of Ancient Britain I said that 'it may be regarded as certain that the draught of Caesar's transports [in 54 B.C.] was much less than five feet.' This statement is misleading though the error does not affect my argument: probably, however, the draught of the beamy shallow vessels which Caesar designed for his second invasion was not more than five feet. Evidently they were much smaller than the Gallic transports which he had used in the previous year; for about 80 + 18 (say 100) of the latter had sufficed to carry two legions with their complement of cavalry, whereas 600 of the former were built to carry five legions and 2000 cavalry. Even the Gallic transports drew so little water that it was possible for the troops whom they carried to jump off them into the sea. Allowing for the projection of the bows, from which the men doubtless jumped, and assuming that the ships sank 18 inches or 2 feet in the bed of the sea (Ancient Britain, p673), we may suppose that their draught was from 8 to 9 feet. Again, the largest of the transports which Napoleon built for the invasion of England were designed to carry each 38 seamen, 120 soldiers, and 12 24‑pounder guns, and their draught was only 8 feet; while the vessels called bateaux cannoniers, which were designed to carry each 6 seamen, 100 soldiers, 2 horses, and 2 guns, only drew 4½ feet of water (E. Desbrière, Projets et tentatives de débarquement, etc. III 1902, pp90, 92).]

The Author's Notes:

1 Among many others Mr. A. G. Peskett (Class. Rev. XXII 1908, p94), Prof. Dennison (Class. Philology, III 1908, p457), M. Camille Jullian (Rev. des études anc. X 1908, p290), and Mr. H. Stuart Jones (Eng. Hist. Rev. XXIV 1909, pp115‑6).

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2 Ancient Britain and the Invasions of Julius Caesar, pp581‑3. I am glad to find that Mr. Stuart Jones (Eng. Hist. Rev. XXIV 1909, p115), with many other competent critics, accepts this conclusion.

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3 See also p574.

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4 Ancient Britain, etc. p566.

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5 The eminent geologist, M. Charles Barrois, of the University of Lille, has very kindly written to me on this question. 'Je ne crois pas,' he says, 'que nous ayons encore des documents assez précis pour arriver à une connaissance décisive et absolue de la question topographique qui vous intéresse.º Il faudrait pour cela faire une série de levées topographiques et de nivellement précis qui n'ont pu être faits encore.

'Je ne puis donc vous donner que mon impression que les conclusions de M. Gosselet [that the coast between Sangatte and Dunkirk extended considerably further seaward in Roman times than now (Ancient Britain, p566)] me paraissent appuyées sur des bases solides, qui n'ont pas été réfutées, et doivent entraîner l'assentiment, la côte s'étendant plus loin à l'époque romaine… Je n'ai rien à ajouter à vos connaissances bibliographiques, qui me paraissent fort complètes.'

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6 Cf. Stoffel, Hist. de Jules César, — Guerre civile, II.110‑1, and pl. 20.

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7 Ancient Britain, etc., pp586‑7. Cf. Boulogne-sur‑mer et la région boulonnaise, I 1899, p31.

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8 Géogr. de la Gaule rom. I 1876, pl. XV.

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9 Mr. H. G. Evelyn-White (Class. Rev. XXII 1908, p205, n9) thinks that it can probably be inferred [that Plautius started from Boulogne] from Suetonius, V.17, — Quare a Massilia Gesoriacum usque pedestri itinere confecto inde [Claudius] transmisit, etc. But Claudius was not accompanied by an army; and it is questionable whether he would have started from Boulogne if he had had to get 800 ships out of the harbour.

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10 Cf. B. G. IV.23, § 2 with § 4.

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11 M. Luchaire (E. Lavisse, Hist. de France, t. III, 1re partie, 1901, p162) appears sceptical as to the number.

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12 Projets et tentatives, etc. III 1902, pp451, 566.

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13 Ib. IV.91, 94‑5; III.141. Between the 1st of May and the 1st of November, 1804, more than 150 vessels were on three several occasions anchored in the roadstead for six or seven successive days; but on each occasion, when they were returning into the harbour, some of them were dispersed or injured (ib. IV.145). Except in the very narrow space formed by the channel of the Liane, which at low water nowhere exceeded 40 metres in breadth and was in many places not more than 20, the ships were generally aground (ib. III pp147‑8). The vessels of least draught could only cross the bar even at spring tides during 4 hours.

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14 Ib. p144.

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15 Some years ago I put the following question to Capt. J. Iron, the harbour-master of Dover:— 'It is certain that Boulogne harbour, that is, the estuary of the river Liane, was much larger in 54 B.C. than it is now. Assume that the harbour was about 2½ miles long, and that its breadth varied from 250 to 700 yards. [See A. E. E. Desjardins, Géogr. de la Gaule rom. vol. I pl. XV.] Would it have been possible for 800 small vessels, which had oars as well as sails, and which drew not more than 3 feet of water, to get out of it in one tide?' Capt. Iron's answer was, 'Yes, because they would have had from one hour after to one hour before low water.' But it is hardly safe to accept Desjardins's delineation of the harbour as absolutely accurate.

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16 See the preceding note.

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17 B. G. V.8, § 2.

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18 Ib. §§ 2, 5‑6.

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19 Ib. § 2.

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20 B. G. IV.23, § 6; B. C. I.31, § 3; II.22, § 3; 25, § 7.

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21 The ships were small, but comparatively broad; 540 of them carried 5 legions with their auxiliaries, camp equipage and stores, 2000 troopers, 2000 cavalry horses, remounts, and baggage cattle (B. G. V.1, § 2; V. 2, § 2; V. 5, § 2; V. 8, §§ 1‑2). Their breadth of beam cannot have been less than 15 feet and was probably rather more. The breadth of one of the great merchant-ships of the Mediterranean, the dimensions of which have been recorded by Lucian, was, as Mr. Torr points out (Ancient Ships, 1894, p24), 'slightly more than a fourth of the length'; and Caesar says that the breadth of the ships which he designed was proportionally greater than that of the Mediterranean craft. The breadth of Napoleon's 'bateaux cannoniers,' which were 60 feet long and drew only 4½ feet of water, was 14 feet (E. Desbrière, Projets et tentatives, etc. III 1902, p90). If Caesar's ships had all been moored in actual contact with one another (!), the line would have been over 4000 yards long.

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22 Probably Labienus's camp was distinct from Caesar's; for if eight legions had occupied one camp, the three which Caesar left with Labienus when he sailed for Britain might have had difficulty in defending it.

Thayer's Note:

a Much too optimistically titled: the paper is only one of several argumentative papers by Holmes and Haverfield over a span of five years. I've put them all online, see the footer bar below.

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