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
In
Italy, where metal in considerable quantity was everywhere required
especially for agricultural purposes and for armour, but few of its
provinces themselves produced the requisite metals, copper (-aes-)
very early made its appearance alongside of cattle as a second
medium of exchange; and so the Latins, who were poor in copper,
designated valuation itself as "coppering" (-aestimatio-).
This
establishment of copper as a general equivalent recognized throughout
the whole peninsula, as well as the simplest numeral signs of
Italian invention to be mentioned more particularly below(17) and
the Italian duodecimal system, may be regarded as traces of this
earliest international intercourse of the Italian peoples while
they still had the peninsula to themselves.
