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
These were the severe years of the Hannibalic war--on the first celebration of the games of Apollo the burgesses were summoned from the circus itself to arms; the superstitious fear peculiar to Italy was feverishly excited, and persons were not wanting who took advantage of the opportunity to circulate Sibylline and prophetic oracles and to recommend themselves to the multitude through their contents and advocacy: we can scarcely blame the government, which was obliged to call for so enormous sacrifices from the burgesses, for yielding in such matters.
But what was once conceded had to be continued; indeed, even in more peaceful times (581) there was added another festival, although of minor importance--the games in honour of Flora. The cost of these new festal amusements was defrayed by the magistrates entrusted with the providing of the respective festivals from their own means: thus the curule aediles had, over and above the old national festival, those of the Mother of the Gods and of Flora; the plebeian aediles had the plebeian festival and that of Ceres, and the urban praetor the Apollinarian games.
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Reference address : https://www.ellopos.net/elpenor/rome/3-11-government-governed.asp?pg=55