Lastly, the territory of the most easterly clan of the Celts, the warlike and numerous Helvetii, was visited with growing frequency by the Germans, so that the Helvetii, who perhaps even apart from this were suffering from over-population through the reflux of their settlers from the territory which they had lost to the north of the Rhine, and besides were liable to be completely isolated from their kinsmen by the settlement of Ariovistus in the territory of the Sequani, conceived the desperate resolution of voluntarily evacuating the territory hitherto in their possession to the Germans, and acquiring larger and more fertile abodes to the west of the Jura, along with, if possible, the hegemony in the interior of Gaul--a plan which some of their districts had already formed and attempted to execute during the Cimbrian invasion.( 32) the Rauraci whose territory (Basle and southern Alsace) was similarly threatened, the remains, moreover, of the Boii who had already at an earlier period been compelled by the Germans to forsake their homes and were now unsettled wanderers, and other smaller tribes, made common cause with the Helvetii.

As early as 693 their flying parties came over the Jura and even as far as the Roman province; their departure itself could not be much longer delayed; inevitably German settlers would then advance into the important region between the lakes of Constance and Geneva forsaken by its defenders.
From the sources of the Rhine to the Atlantic Ocean the German tribes were in motion; the whole line of the Rhine was threatened by them; it was a moment like that when the Alamanni and the Franks threw themselves on the falling empire of the Caesars; and even now there seemed on the eve of being carried into effect against the Celts that very movement which was successful five hundred years afterwards against the Romans.
Caesar Proceeds to Gaul Caesar's Army Under these circumstances the new governor Gaius Caesar arrived in the spring of 696 in Narbonese Gaul, which had been added by decree of the senate to his original province embracing Cisalpine Gaul along with Istria and Dalmatia.

His office, which was committed to him first for five years (to the end of 700), then in 699 for five more (to the end of 705), gave him the right to nominate ten lieutenants of propraetorian rank, and (at least according to his own interpretation) to fill up his legions, or even to form new ones at his discretion out of the burgess-population--who were especially numerous in Cisalpine Gaul--of the territory under his sway.

The army, which he received in the two provinces, consisted, as regards infantry of the line, of four legions trained and inured to war, the seventh, eighth, ninth, and tenth, or at the utmost 24,000 men, to which fell to be added, as usual, the contingents of the subjects.

The cavalry and light-armed troops, moreover, were represented by horsemen from Spain, and by Numidian, Cretan, and Balearic archers and slingers.