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 task, however, of determining the degree of culture which the Indo-Germans had attained before the separation of the stocks properly belongs to the general history of the ancient world. It is on the other hand the special task of Italian history to ascertain, so far as it is possible, what was the state of the Graeco-Italian nation when the Greeks and the Italians parted. Nor is this a superfluous labour; we reach by means of it the stage at which Italian civilization commenced, the starting-point of the national history.
While it is probable that the Indo-Germans led a pastoral life and were acquainted with the cereals, if at all, only in their wild state, all indications point to the conclusion that the Graeco-Italians were a grain-cultivating, perhaps even a vine-cultivating, people. The evidence of this is not simply the knowledge of agriculture itself common to both, for this does not upon the whole warrant the inference of community of origin in the peoples who may exhibit it. An historical connection between the Indo-Germanic agriculture and that of the Chinese, Aramaean, and Egyptian stocks can hardly be disputed; and yet these stocks are either alien to the Indo-Germans, or at any rate became separated from them at a time when agriculture was certainly still unknown.
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Reference address : https://www.ellopos.net/elpenor/rome/1-02-earliest-migrations-italy.asp?pg=16