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
An attempt of this kind which was made on a
route hitherto little known to the Romans, in the innermost recess of
the Adriatic, and still more, as if would seem, the project of Philip
of Macedonia for invading Italy from the east as Hannibal had done
from the west, gave occasion to the founding of a fortress in the
extreme north-eastern corner of Italy--Aquileia, the most northerly of
the Italian colonies (571-573)--which was intended not only to close
that route for ever against foreigners, but also to secure the command
of the gulf which was specially convenient for navigation, and to
check the piracy which was still not wholly extirpated in those
waters.
The establishment of Aquileia led to a war with the Istrians
(576, 577), which was speedily terminated by the storming of some
strongholds and the fall of the king, Aepulo, and which was remarkable
for nothing except for the panic, which the news of the surprise of
the Roman camp by a handful of barbarians called forth in the fleet
and throughout Italy.