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
The well judged preference given at the same
time to the Greeks of Lower Italy over their Sabellian neighbours,
particularly to the considerable communities of Neapolis, Rhegium,
Locri, Thurii, and Heraclea, and their similar exemption under the
like conditions from furnishing contingents to the land army,
completed the network drawn by Rome around the coasts of Italy.
But with a statesmanlike sagacity, from which the succeeding
generations might have drawn a lesson, the leading men of the Roman
commonwealth perceived that all these coast fortifications and coast
garrisons could not but prove inadequate, unless the war marine of
the state were again placed on a footing that should command respect.