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 expedients of which the nobility availed themselves were as
various as political paltriness could suggest. Instead of deciding
at once the question as to the admission or exclusion of the plebeians
at the elections, they conceded what they were compelled to concede
only with reference to the elections immediately impending.
The vain
struggle was thus annually renewed whether patrician consuls or
military tribunes from both orders with consular powers should be
nominated; and among the weapons of the aristocracy this mode of
conquering an opponent by wearying and annoying him proved by no
means the least effective.