Note 2696 — PORTUS ITIUS
Reading edition
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.