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
In the light of these regulations the dictatorship is doubtless to be conceived as an institution which arose at the same time with the consulship, and which was designed, especially in the event of war, to obviate for a time the disadvantages of divided power and to revive temporarily the regal authority; for in war more particularly the equality of rights in the consuls could not but appear fraught with danger; and not only positive testimonies, but above all the oldest names given to the magistrate himself and his assistant, as well as the limitation of the office to the duration of a summer campaign, and the exclusion of the -provocatio- attest the pre-eminently military design of the original dictatorship.
On the whole, therefore, the consuls continued to be, as the kings had been, the supreme administrators, judges, and generals; and even in a religious point of view it was not the -rex sacrorum- (who was only nominated that the name might be preserved), but the consul, who offered prayers and sacrifices for the community, and in its name ascertained the will of the gods with the aid of those skilled in sacred lore.
Against cases of emergency, moreover, a power was retained of reviving at any moment, without previous consultation of the community, the full and unlimited regal authority, so as to set aside the limitations imposed by the collegiate arrangement and by the special curtailments of jurisdiction. In this way the problem of legally retaining and practically restricting the regal authority was solved in genuine Roman fashion with equal acuteness and simplicity by the nameless statesmen who worked out this revolution.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/2-01-constitution-magistrate.asp?pg=18