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 "people"
accordingly ratified the Livian laws as readily as it had before
ratified the Sempronian. It then, as usual, repaid its latest, by
inflicting a gentle blow on its earlier, benefactor, declining to
re-elect him when he stood for the third time as a candidate for the
tribunate for the year 633; on which occasion, however, there are
alleged to have been unjust proceedings on the part of the tribune
presiding at the election, who had been formerly offended by
Gracchus.
Thus the foundation of his despotism gave way beneath
him. A second blow was inflicted on him by the consular elections,
which not only proved in a general sense adverse to the democracy,
but which placed at the head of the state Lucius Opimius, who as
praetor in 629 had conquered Fregellae, one of the most decided
and least scrupulous chiefs of the strict aristocratic party,
and a man firmly resolved to get rid of their dangerous antagonist
at the earliest opportunity.
