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
Hitherto the measurement of time had been treated in Rome with barbarous indifference, but matters were now at least in some degree improved. With the erection of the first sundial in the Roman Forum in 491 the Greek hour (--ora--, -hora-) began to come into use at Rome: it happened, however, that the Romans erected a sundial which had been prepared for Catana situated four degrees farther to the south, and were guided by this for a whole century. Towards the end of this epoch we find several persons of quality taking an interest in mathematical studies.
Manius Acilius Glabrio (consul in 563) attempted to check the confusion of the calendar by a law, which allowed the pontifical college to insert or omit intercalary months at discretion: if the measure failed in its object and in fact aggravated the evil, the failure was probably owing more to the unscrupulousness than to the want of intelligence of the Roman theologians. Marcus Fulvius Nobilior (consul in 565), a man of Greek culture, endeavoured at least to make the Roman calendar more generally known.
Gaius Sulpicius Gallus (consul in 588), who not only predicted the eclipse of the moon in 586 but also calculated the distance of the moon from the earth, and who appears to have come forward even as an astronomical writer, was regarded on this account by his contemporaries as a prodigy of diligence and acuteness.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/3-14-literature-art.asp?pg=104