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
But the hypothesis that the Cimbri, as well as the similar horde of the Teutones which afterwards joined them, belonged essentially not to the Celtic nation, to which the Romans at first assigned them, but to the Germanic, is supported by the most definite facts: viz., by the appearance of two small tribes of the same name--remnants apparently left behind in their primitive seats--the Cimbri in the modern Denmark, the Teutones in the north-east of Germany in the neighbourhood of the Baltic, where Pytheas, a contemporary of Alexander the Great, makes mention of them thus early in connection with the amber trade; by the insertion of the Cimbri and Teutones in the list of the Germanic peoples among the Ingaevones alongside of the Chauci; by the judgment of Caesar, who first made the Romans acquainted with the distinction between the Germans and the Celts, and who includes the Cimbri, many of whom he must himself have seen, among the Germans; and lastly, by the very names of the peoples and the statements as to their physical appearance and habits in other respects, which, while applying to the men of the north generally, are especially applicable to the Germans.
On the other hand it is conceivable enough that such a horde, after having been engaged in wandering perhaps for many years and having in its movements near to or within the land of the Celts doubtless welcomed every brother-in-arms who joined it, would include a certain amount of Celtic elements; so that it is not surprising that men of Celtic name should be at the head of the Cimbri, or that the Romans should employ spies speaking the Celtic tongue to gain information among them.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/4-05-peoples-north.asp?pg=25