mised to become
not merely brave guardians of the frontier but also better subjects
of Rome, for their nationality severed them from the Celts,
and their own interest in the preservation of their newly-won
settlements severed them from their countrymen across the Rhine,
so that in their isolated position they could not avoid adhering
to the central power. Caesar here, as everywhere, preferred
conquered foes to doubtful friends; he left the Germans settled
by Ariovistus along the left bank of the Rhine--the Triboci
about Strassburg, the Nemetes about Spires, the Vangiones
about Worms--in possession of their new abodes, and entrusted them
with the guarding of the Rhine-frontier against their countrymen.(37)
The Suebi, who threatened the territory of the Treveri on the middle
Rhine, on receiving news of the defeat of Ariovistus, again retreated
into the interior of Germany; on which occasion they sustained
considerable loss by the way at the hands of the adjoining tribes.

The Rhine Boundary

The consequences of this one campaign were immense; they were felt
for many centuries after. The Rhine had become the boundary
of the Roman empire against the Germans. In Gaul, which was no longer
able to govern itself, the Romans had hitherto ruled on the south
coast, while lately the Germans had attempted to establish themselves
farther up. The recent events had decided that Gaul was to succumb
not merely in part but wholly to the Roman supremacy,
and that the natural boundary presented by the mighty river was also
to become the political boundary. The senate in its better times
had not rested, till the dominion of Rome had reached the natural
bounds of Italy--the Alps and the Mediterranean--and its adjacent
islands. The enlarged empire also needed a similar military
rounding off; but the present government left the matter
to accident, and sought at most to see, not that the frontiers
were capable of defence, but that they should not need to be defended
directly by itself. People felt that now another spirit
and another arm began to guide the destinies of Rome.

Subjugation of Gaul
Belgic Expedition

The foundations of the future edifice were laid; but in order
to finish the building and completely to secure the recognition
of the Roman rule by the Gauls, and that of the Rhine-frontier by
the Germans, very much still remained to be done. All central Gaul
indeed from the Roman frontier as far up as Chartres and Treves