[2695] Portus Itius, p. 5.
[2696] J. F. Henry argues (Essai ... sur l’arrondissement communal de Boulogne-sur-mer, 1810, pp. 54-5) that Caesar could only have estimated the distance from the Portus Itius to Britain by making the voyage; that, as he was carried out of his course on the second voyage, the one by which he estimated the distance must have been the first; and consequently that in 55 as in 54 B.C. he must have sailed from the Portus Itius.
But Henry forgot that Volusenus, whom Caesar sent in 55 B.C. to reconnoitre the British coast, may have made the estimate. Or Caesar may have accepted the estimate of merchants, of seamen, or of Commius: it is useless to guess.
[2697] Portus Itius, p. 9.
[2698] In support of the view that Caesar reckoned the distance to the nearest port of Britain, Heller (Zeitschrift für allgemeine Erdkunde, xviii, 1865, pp. 172-3) argues (1) that if he had intended to indicate the distance to his landing-place, he would probably have written, not (quo ex portu commodissimum) in Britanniam (traiectum esse cognoverat, &c.) but ad eum locum quo est descensum (‘to the spot where the disembarkation took place’); (2) that when Strabo estimated the length of Caesar’s voyage at 320 stades, or 40 Roman miles, he must either have found (milium passuum) XXXX, which is not in any extant MS., in his copy of the Commentaries, or have concluded, from other information, that Caesar had underestimated the distance; and in either case the fact that he expressly mentions the time which Caesar took to reach his anchorage shows that he did not take into account the additional 7 miles which separated the anchorage from the landing-place.
It will be seen, however, that, although I agree with Heller’s conclusion, the proofs by which I shall establish the identity of the Portus Itius are wholly independent of it.
[2699] See pp. 592-3, infra.
[2700] See p. 619, infra.
[2701] Cf. Mommsen, Röm. Gesch., iii, 1889, pp. 269-70, note (Eng. trans., v, 1894, p. 63, note).
[2702] Nat. Hist., iv, 16 (30), § 103.