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
And, as if this were not enough,
immediately after the battle on the Trasimene lake, the cavalry of
the army of Ariminum under Gaius Centenius, 4000 strong, which Gnaeus
Servilius had sent forward for the temporary support of his colleague
while he himself advanced by slow marches, was likewise surrounded by
the Phoenician army, and partly slain, partly made prisoners.
All
Etruria was lost, and Hannibal might without hindrance march on Rome.
The Romans prepared themselves for the worst; they broke down the
bridges over the Tiber, and nominated Quintus Fabius Maximus dictator
to repair the walls and conduct the defence, for which an army of
reserve was formed.
At the same time two new legions were summoned
under arms in the room of those annihilated, and the fleet, which
might become of importance in the event of a siege, was put in order.
