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
At the very beginning of the fifth century, Rome had in similar
circumstances sent to the field a burgess-army equally strong;(11)
after the great extensions of the burgess-domain in the course of that
century the number of full burgesses capable of bearing arms must at
least have doubled.
But far more than in the number of men capable of
bearing arms, Rome excelled in the effective condition of the burgess-
soldier. Anxious as the Carthaginian government was to induce its
citizens to take part in military service, it could neither furnish
the artisan and the manufacturer with the bodily vigour of the
husbandman, nor overcome the native aversion of the Phoenicians to
warfare.
In the fifth century there still fought in the Sicilian
armies a "sacred band" of 2500 Carthaginians as a guard for the
general; in the sixth not a single Carthaginian, officers excepted,
was to be met with in the Carthaginian armies, e. g. in that of Spain.
The Roman farmers, again, took their places not only in the muster-
roll, but also in the field of battle.