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
When the small holdings ceased to yield any substantial clear return,
the farmers were irretrievably ruined, and the more so that they
gradually, although more slowly than the other classes, lost the moral
tone and frugal habits of the earlier ages of the republic It was
merely a question of time, how rapidly the hides of the Italian
farmers would, by purchase or by resignation, become merged in
the larger estates.
Culture of Oil and Wine, and Rearing of Cattle
The landlord was better able to maintain himself than the farmer.
The former produced at a cheaper rate than the latter, when, instead
of letting his land according to the older system to petty temporary
lessees, he caused it according to the newer system to be cultivated
by his slaves. Accordingly, where this course had not been adopted
even at an earlier period,(12) the competition of Sicilian slave-corn
compelled the Italian landlord to follow it, and to have the work
performed by slaves without wife or child instead of families of free
labourers.