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
The mainland of Italy proper, south of the Apennines, enjoyed profound peace after the fall of Tarentum: the six days' war with Falerii (513) was little more than an interlude. But towards the north, between the territory of the confederacy and the natural boundary of Italy--the chain of the Alps--there still extended a wide region which was not subject to the Romans.
What was regarded as the boundary of Italy on the Adriatic coast was the river Aesis immediately above Ancona. Beyond this boundary the adjacent properly Gallic territory as far as, and including, Ravenna belonged in a similar way as did Italy proper to the Roman alliance; the Senones, who had formerly settled there, were extirpated in the war of 471-2,(12) and the several townships were connected with Rome, either as burgess-colonies, like Sena Gallica,(13) or as allied towns, whether with Latin rights, like Ariminum,(14) or with Italian rights, like Ravenna.
12. Cf. III. VII. The Senones Annihilated
13. Cf. III. VII. Breach between Rome and Tarentum
14. Cf. III. VII. Construction of New Fortresses and Roads
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Reference address : https://www.ellopos.net/elpenor/rome/3-03-extension-italy.asp?pg=26