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
At some time or other after the expulsion of the Tarquins from Rome the arrangements of the Latin communities must have been throughout revised in accordance with the scheme of the consular constitution.
This adjustment of the Latin constitutions in conformity with that of the leading city may possibly belong only to a later period; but internal probability rather favours the supposition that the Roman nobility, after having effected the abolition of royalty for life at home, suggested a similar change of constitution to the communities of the Latin confederacy, and at length introduced aristocratic government everywhere in Latium-- notwithstanding the serious resistance, imperilling the stability of the Romano-Latin league itself, which seems to have been offered on the one hand by the expelled Tarquins, and on the other by the royal clans and by partisans well affected to monarchy in the other communities of Latium.
The mighty development of the power of Etruria that occurred at this very time, the constant assaults of the Veientes, and the expedition of Porsena, may have materially contributed to secure the adherence of the Latin nation to the once-established form of union, or, in other words, to the continued recognition of the supremacy of Rome, and disposed them for its sake to acquiesce in a change of constitution for which, beyond doubt, the way had been in many respects prepared even in the bosom of the Latin communities, nay perhaps to submit even to an enlargement of the rights of hegemony.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/2-05-subjugation-latins-campanians.asp?pg=7