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
There were instances even already
of Roman burgesses acquiring landed property beyond the Roman
frontier, and turning it to profit after the Italian fashion;
there is mention, for example, of Roman estates in the canton
of the Segusiavi (near Lyons) as early as about 673. Beyond doubt it
was a consequence of this that, as already mentioned(24) in free Gaul
itself, e. g. among the Arverni, the Roman language was not unknown
even before the conquest; although this knowledge was presumably
still restricted to few, and even the men of rank in the allied
canton of the Haedui had to be conversed with through interpreters.
Just as the traffickers in fire-water and the squatters led the way
in the occupation of North America, so these Roman wine-traders
and landlords paved the way for, and beckoned onward, the future
conqueror of Gaul. How vividly this was felt even on the opposite
side, is shown by the prohibition which one of the most energetic
tribes of Gaul, the canton of the Nervii, like some German peoples,
issued against trafficking with the Romans.