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
All these burgesses domiciled outside of Rome were without a commonwealth and an administration of their own; on the assigned territory there arose at the most market-villages (-fora et conciliabula-). In a position not greatly different were placed the burgesses sent out to the so-called maritime colonies mentioned above, who were likewise left in possession of the full burgess-rights of Rome, and whose self-administration was of little moment.
Towards the close of this period the Roman community appears to have begun to grant full burgess-rights to the adjoining communities of passive burgesses who were of like or closely kindred nationality; this was probably done first for Tusculum,(30) and so, presumably, also for the other communities of passive burgesses in Latium proper, then at the end of this period (486) was extended to the Sabine towns, which doubtless were even then essentially Latinized and had given sufficient proof of their fidelity in the last severe war.
30. That Tusculum as it was the first to obtain passive burgess-rights (Cf. II. V. Crises within the Romano-Latin League) was also the first to exchange these for the rights of full burgesses, is probable in itself and presumably it is in the latter and not in the former respect that the town is named by Cicero (pro Mur. 8, 19) -municipium antiquissimum-.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/2-07-pyrrhus-rome-italy.asp?pg=68