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
Any concessions that did take place, came not so much from the pressure
of the democracy as from the attempts at mediation of the moderate
aristocracy. But of the two laws which the single still surviving
leader of this section Gaius Cotta carried in his consulate of 679,
that which concerned the tribunals was again set aside
in the very next year; and the second, which abolished the Sullan
enactment that those who had held the tribunate should be disqualified
for undertaking other magistracies, but allowed the other limitations
to continue, merely--like every half-measure--excited the displeasure
of both parties.
The party of conservatives friendly to reform which lost
its most notable head by the early death of Cotta occurring soon
after (about 681) dwindled away more and more--crushed between
the extremes, which were becoming daily more marked. But of these
the party of the government, wretched and remiss as it was,
necessarily retained the advantage in presence of the equally
wretched and equally remiss opposition.