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
Upon the whole
the Sabines maintained their footing in the mountains, as in the
district bordering on Latium which has since been called by their
name, and so too in the Volscian land, presumably because the Latin
population did not extend thither or was there less dense; while
on the other hand the well-peopled plains were better able to offer
resistance to the invaders, although they were not in all cases
able or desirous to prevent isolated bands from gaining a footing,
such as the Tities and afterwards the Claudii in Rome.(2) In this
way the stocks here became variously mingled, a state of things
which serves to explain the numerous relations that subsisted
between the Volscians and Latins, and how it happened that their
district, as well as Sabina, afterwards became so early and speedily
Latinized.
