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
Domestic and family life in general were represented by the festival of the goddess of the house and of the spirits of the storechamber, Vesta and the Penates (-Vestalia-, June 9); the festival of the goddess of birth(2) (-Matralia-, June 11); the festival of the blessing of children, dedicated to Liber and Libera (-Liberalia-, March 17), the festival of departed spirits (-Feralia-, February 21), and the three days' ghost-celebration (-Lemuria- May 9, 11, 13); while those having reference to civil relations were the two--otherwise to us somewhat obscure--festivals of the king's flight (-Regifugium-, February 24) and of the people's flight (-Poplifugia-, July 5), of which at least the last day was devoted to Jupiter, and the festival of the Seven Mounts (-Agonia- or -Septimontium-, December 11).
2. This was, to all appearance, the original nature of the "morning-mother" or -Mater matuta-; in connection with which we may recall the circumstance that, as the names Lucius and especially -Manius- show, the morning hour was reckoned as lucky for birth. -Mater matuta-probably became a goddess of sea and harbour only at a later epoch under the influence of the myth of Leucothea; the fact that the goddess was chiefly worshipped by women tells against the view that she was originally a harbour-goddess.
A special day (-agonia-, January 9) was also consecrated to Janus, the god of beginning. The real nature of some other days--that of Furrina (July 25), and that of the Larentalia devoted to Jupiter and Acca Larentia, perhaps a feast of the Lares (December 23)--is no longer known.
This table is complete for the immoveable public festivals; and--although by the side of these standing festal days there certainly occurred from the earliest times changeable and occasional festivals--this document, in what it says as well as in what it omits, opens up to us an insight into a primitive age otherwise almost wholly lost to us.
The union of the Old Roman community and the Hill-Romans had indeed already taken place when this table of festivals was formed, for we find in it Quirinus alongside of Mars; but, when this festival-list was drawn up, the Capitoline temple was not yet in existence, for Juno and Minerva are absent; nor was the temple of Diana erected on the Aventine; nor was any notion of worship borrowed from the Greeks.
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Reference address : https://www.ellopos.net/elpenor/rome/1-12-religion.asp?pg=5