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
This agreement cannot have been accidental, but must have been either a remnant of the primitive connection between the peoples, or a result of the earliest international intercourse; and the probabilities preponderate in favour of the latter hypothesis. The city-festival, in the form in which we are acquainted with it, was not one of the oldest institutions of Rome, for the Circus itself was only laid out in the later regal period;(12) and just as the reform of the constitution then took place under Greek influence,(13) the city-festival may have been at the same time so far transformed as to combine Greek races with, and eventually to a certain extent to substitute them for, an older mode of amusement--the "leap" (-triumpus-,(14)), and possibly swinging, which was a primitive Italian custom and long continued in use at the festival on the Alban mount.
12. Cf. I. VII. Servian Wall
13. Cf. I. VI. Time and Occasion of the Reform
14. Cf. I. II. Religion
Moreover, while there is some trace of the use of the war-chariot in actual warfare in Greece, no such trace exists in Latium. Lastly, the Greek term στάδιον (Doric σπάδιον) was at a very early period transferred to the Latin language, retaining its signification, as -spatium-; and there exists even an express statement that the Romans derived their horse and chariot races from the people of Thurii, although, it is true, another account derives them from Etruria. It thus appears that, in addition to the impulses imparted by the Greeks in music and poetry, the Romans were indebted to them for the fruitful idea of gymnastic competitions.
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Reference address : https://www.ellopos.net/elpenor/rome/1-15-art.asp?pg=21