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
A still more important circumstance was, that, probably on the institution of the curule aedileship (387) which was from the first entrusted with the preparation and oversight of the festival,(3) it lost its extraordinary character and its reference to a special vow made by the general, and took its place in the series of the ordinary annually recurring festivals as the first of all.
3. Cf. II. III. Curule Aedileship
Nevertheless the government adhered to the practice of allowing the spectacle proper --namely the chariot-race, which was the principal performance--to take place not more than once at the close of the festival. On the other days the multitude were probably left mainly to furnish amusement for themselves, although musicians, dancers, rope-walkers, jugglers, jesters and such like would not fail to make their appearance on the occasion, whether hired or not But about the year 390 an important change occurred, which must have stood in connection with the fixing and prolongation of the festival, that took place perhaps about the same time.
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