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
The profound and fearful idea of substitution also meets us here: when the gods of the community were angry and nobody could be laid hold of as definitely guilty, they might be appeased by one who voluntarily gave himself up (-devovere se-); noxious chasms in the ground were closed, and battles half lost were converted into victories, when a brave burgess threw himself as an expiatory offering into the abyss or upon the foe.
The "sacred spring" was based on a similar view; all the offspring whether of cattle or of men within a specified period were presented to the gods. If acts of this nature are to be called human sacrifices, then such sacrifices belonged to the essence of the Latin faith; but we are bound to add that, far back as our view reaches into the past, this immolation, so far as life was concerned, was limited to the guilty who had been convicted before a civil tribunal, or to the innocent who voluntarily chose to die. Human sacrifices of a different description run counter to the fundamental idea of a sacrificial act, and, wherever they occur among the Indo-Germanic stocks at least, are based on later degeneracy and barbarism.
They never gained admission among the Romans; hardly in a single instance were superstition and despair induced, even in times of extreme distress, to seek an extraordinary deliverance through means so revolting. Of belief in ghosts, fear of enchantments, or dealing in mysteries, comparatively slight traces are to be found among the Romans.
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Reference address : https://www.ellopos.net/elpenor/rome/1-12-religion.asp?pg=21