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
Presumably about the same time the full right of free migration allowed to the Latin communities hitherto established--the title of every one of their burgesses to gain by transmigration to Rome full burgess-rights there--was, for the Latin colonies of later erection, restricted to those persons who had attained to the highest office of the community in their native home; these alone were allowed to exchange their colonial burgess-rights for the Roman. This clearly shows the complete revolution in the position of Rome.
So long as Rome was still but one among the many urban communities of Italy, although that one might be the first, admission even to the unrestricted Roman franchise was universally regarded as a gain for the admitting community, and the acquisition of that franchise by non-burgesses was facilitated in every way, and was in fact often imposed on them as a punishment. But after the Roman community became sole sovereign and all the others were its servants, the state of matters changed.
The Roman community began jealously to guard its franchise, and accordingly put an end in the first instance to the old full liberty of migration; although the statesmen of that period were wise enough still to keep admission to the Roman franchise legally open at least to the men of eminence and of capacity in the highest class of subject communities. The Latins were thus made to feel that Rome, after having subjugated Italy mainly by their aid, had now no longer need of them as before.
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Reference address : https://www.ellopos.net/elpenor/rome/2-07-pyrrhus-rome-italy.asp?pg=75