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 Samnites as well as the Latins threw themselves upon the
Etruscans; and hardly had their Campanian settlement been cut off
from the motherland in consequence of the battle of Cumae, when it
found itself no longer able to resist the assaults of the Sabellian
mountain tribes. Capua, the capital, fell in 330; and the Tuscan
population there was soon after the conquest extirpated or expelled by
the Samnites.
It is true that the Campanian Greeks also, isolated and
weakened, suffered severely from the same invasion: Cumae itself was
conquered by the Sabellians in 334. But the Greeks maintained their
ground at Neapolis especially, perhaps with the aid of the Syracusans,
while the Etruscan name in Campania disappeared from history
--excepting some detached Etruscan communities, which prolonged
a pitiful and forlorn existence there.
Events still more momentous, however, occurred about the same time in
Northern Italy. A new nation was knocking at the gates of the Alps:
it was the Celts; and their first pressure fell on the Etruscans.