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
As a basis for
the notion of a whole made up of equal parts, nothing so readily
suggests itself as the hand with its five, or the hands with their
ten, fingers; upon this rests the decimal system. We have already
observed that these elements of all numeration and measuring
reach back not merely beyond the separation of the Greek and Latin
stocks, but even to the most remote primeval times.
The antiquity
in particular of the measurement of time by the moon is demonstrated
by language;(1) even the mode of reckoning the days that elapse
between the several phases of the moon, not forward from the phase
on which it had entered last, but backward from that which was
next to be expected, is at least older than the separation of the
Greeks and Latins.
