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
From the
outset and by virtue of the whole tenor of his life a cosmopolite, he
had the skill to appropriate the distinctive features of the nations
among which he lived--Greek, Latin, and even Oscan--without devoting
himself absolutely to any cne of them; and while the Hellenism of the
earlier Roman poets was the result rather than the conscious aim of
their poetic activity, and accordingly they at least attempted more or
less to take their stand on national ground, Ennius on the contrary is
very distinctly conscious of his revolutionary tendency, and evidently
labours with zeal to bring into vogue neologico-Greek ideas among
the Italians.
His most serviceable instrument was tragedy. The
remains of his tragedies show that he was well acquainted with the
whole range of the Greek tragic drama and with Aeschylus and Sophocles
in particular; it is the less therefore the result of accident, that
he has modelled the great majority of his pieces, and all those that
attained celebrity, on Euripides. In the selection and treatment he
was doubtless influenced partly by external considerations.