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
In the circumstances of primitive times transport and acclimatizing are more difficult in the case of plants than of animals; and the cultivation of rice among the Indians, that of wheat and spelt among the Greeks and Romans, and that of rye and oats among the Germans and Celts, may all be traceable to a common system of primitive tillage. On the other hand the name of one cereal common to the Greeks and Indians only proves, at the most, that before the separation of the stocks they gathered and ate the grains of barley and spelt growing wild in Mesopotamia,(3) not that they already cultivated grain. While, however, we reach no decisive result in this way, a further light is thrown on the subject by our observing that a number of the most important words bearing on this province of culture occur certainly in Sanscrit, but all of them in a more general signification. -Agras-among the Indians denotes a level surface in general; -kurnu-, anything pounded; -aritram-, oar and ship; -venas-, that which is pleasant in general, particularly a pleasant drink.
3. Barley, wheat, and spelt were found growing together in a wild state on the right bank of the Euphrates, north-west from Anah (Alph. de Candolle, Geographie botanique raisonnee, ii. p. 934). The growth of barley and wheat in a wild state in Mesopotamia had already been mentioned by the Babylonian historian Berosus (ap. Georg. Syncell. p. 50 Bonn.).
The words are thus very ancient; but their more definite application to the field (-ager-), to the grain to be ground (-granum-), to the implement which furrows the soil as the ship furrows the surface of the sea (-aratrum-), to the juice of the grape (-vinum-), had not yet taken place when the earliest division of the stocks occurred, and it is not to be wondered at that their subsequent applications came to be in some instances very different, and that, for example, the corn intended to be ground, as well as the mill for grinding it (Gothic -quairinus-, Lithuanian -girnos-, (4)) received their names from the Sanscrit -kurnu-. We may accordingly assume it as probable, that the primeval Indo-Germanic people were not yet acquainted with agriculture, and as certain, that, if they were so, it played but a very subordinate part in their economy; for had it at that time held the place which it afterwards held among the Greeks and Romans, it would have left a deeper impression upon the language.
4. Scotch -quern-. Mr. Robertson.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/1-02-earliest-migrations-italy.asp?pg=12