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 accused was one
Gaius Rabirius, who, if he had not killed Saturninus,
had at least paraded with his cut-off head at the tables
of men of rank, and who moreover was notorious among the Apulian
landholders for his kidnapping and his bloody deeds.
The object,
if not of the accuser himself, at any rate of the more sagacious men
who backed him, was not at all to make this pitiful wretch
die the death of the cross; they were not unwilling to acquiesce,
when first the form of the impeachment was materially modified
by the senate, and then the assembly of the people called to pronounce
sentence on the guilty was dissolved under some sort of pretext
by the opposite party--so that the whole procedure was set aside.
At all events by this process the two palladia of Roman freedom,
the right of the citizens to appeal and the inviolability of the tribunes
of the people, were once more established as practical rights,
and the legal basis on which the democracy rested was adjusted afresh.