An immigration of Belgic Celts to Britain continuing for a considerable time seems indicated by the names of English tribes on both banks of the Thames borrowed from Belgic cantons; such as the Atrebates, the Belgae, and even the Britanni themselves, which word appears to have been transferred from the Brittones settled on the Somme below Amiens first to an English canton and then to the whole island.

The English gold coinage was also derived from the Belgic and originally identical with it.
11.

The first levy of the Belgic cantons exclusive of the Remi, that is, of the country between the Seine and the Scheldt and eastward as far as the vicinity of Rheims and Andernach, from 9000 to 10,000 square miles, is reckoned at about 300,000 men; in accordance with which, if we regard the proportion of the first levy to the whole men capable of bearing arms specified for the Bellovaci as holding good generally, the number of the Belgae capable of bearing arms would amount to 500,000 and the whole population accordingly to at least 2,000,000.

The Helvetii with the adjoining peoples numbered before their migration 336,000; if we assume that they were at that time already dislodged from the right bank of the Rhine, their territory may be estimated at nearly 1350 square miles.

Whether the serfs are included in this, we can the less determine, as we do not know the form which slavery assumed amongst the Celts; what Caesar relates (i.