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
But
these obstacles might be surmounted by an energetic will; and both the
contending parties construed the summons of the Tarentine envoys that
they should desist from the strife as meant in earnest. The Samnites,
as the weaker, showed themselves ready to comply with it; the Romans
replied by hoisting the signal for battle.
Reason and honour dictated
to the Tarentines the propriety of now following up the haughty
injunction of their envoys by a declaration of war against Rome; but
in Tarentum neither reason nor honour characterized the government,
and they had simply been trifling in a very childish fashion with
very serious matters.
No declaration of war against Rome took place;
in its stead they preferred to support the oligarchical party in the
Sicilian towns against Agathocles of Syracuse who had at a former
period been in the Tarentine service and had been dismissed in
disgrace, and following the example of Sparta, they sent a fleet
to the island--a fleet which would have rendered better service
in the Campanian seas (440).