importance of Corbilo as the emporium for trade with Britain would rapidly disappear.
As a matter of fact, the history of South-Eastern Britain points directly to such a shifting. It was not very long before the time of Cæsar that the Belgic tribes first established themselves in Britain. The tradition of their settlement was still fresh (Cæsar, B. G., v, 12). In fact, the Belgic conquest was still in progress, for it is probable that between the time of Cæsar and that of Claudius they advanced considerably further westward. We have unfortunately no evidence to show whether these settlements had already commenced in the days of Pytheas. An obscure passage of Strabo (iv, 201) has often been cited as showing that Pytheas found the natives of Britain cultivating corn and threshing it in covered barns instead of threshing-floors, as in the South. If the passage really referred to Britain it would point almost certainly to the settlement of the Belgæ in Britain. For, according to Cæsar, it was only the newly settled Belgæ who cultivated corn, as the aborigines of the inland districts subsisted on the milk and flesh of their flocks and herds (Cæsar, B. G., iv, 12). But a careful study of the passage referred to will show that it is purely gratuitous to assume it as referring to Britain. Posidonius, as we learn from Diodorus, found the Britons cultivating corn when, more than two centuries later, he visited the island. It is obvious that when the Belgic tribes crossed over and made permanent settlements on the south-east coast of Britain, that the course of trade would pass regularly from Kent into Northern France, and that the old route by Armorica, Corbilo, and the Loire would fall into disuse. Hence it is that we find from Diodorus that at the time of Posidonius the tin evidently was brought across the Straits, for he describes it as being conveyed on pack-horses a journey of thirty days across Gaul. It is obvious that the tin so conveyed was not brought by the Loire route, since in that case the distance for overland transit would have been very short.
