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
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
Abolition of the Monarchy
The common assembly lost its political importance; and even the power of the prince, which should have checked the encroachments of the nobility, succumbed to it among the Celts as well as in Latium. In place of the king came the "judgment-worker" or -Vergobretus-,(19) who was like the Roman consul nominated only for a year.
19. From the Celtic words -guerg- = worker and -breth- = judgment.
So far as the canton still held together at all, it was led by the common council, in which naturally the heads of the aristocracy usurped the government. Of course under such circumstances there was agitation in the several clans much in the same way as there had been agitation in Latium for centuries after the expulsion of the kings: while the nobility of the different communities combined to form a separate alliance hostile to the power of the community, the multitude ceased not to desire the restoration of the monarchy; and not unfrequently a prominent nobleman attempted, as Spurius Cassius had done in Rome, with the support of the mass of those belonging to the canton to break down the power of his peers, and to reinstate the crown in its rights for his own special benefit.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/5-07-subjugation-west.asp?pg=30