Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
German Settlements on the Left Bank of the Rhine
Thus brilliantly the Roman rule announced its advent to the mighty stream, which the Italian soldiers here saw for the first time; by a single fortunate battle the line of the Rhine was won. The fate of the German settlements on the left bank of the Rhine lay in the hands of Caesar; the victor could destroy them, but he did not do so.
The neighbouring Celtic cantons--the Sequani, Leuci, Mediomatrici--were neither capable of self-defence nor trustworthy; the transplanted Germans promised 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)
37. This seems the simplest hypothesis regarding the origin of these Germanic settlements. That Ariovistus settled those peoples on the middle Rhine is probable, because they fight in his army (Caes. i. 51) and do not appear earlier; that Caesar left them in possession of their settlements is probable, because he in presence of Ariovistus declared himself ready to tolerate the Germans already settled in Gaul (Caes. i. 35, 43), and because we find them afterwards in these abodes. Caesar does not mention the directions given after the battle concerning these Germanic settlements, because he keeps silence on principle regarding all the organic arrangements made by him in Gaul.
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.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/5-07-subjugation-west.asp?pg=72