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
Nor need it surprise us that Caesar, anything but a political antiquary, went back five hundred years to find the model for his new state; for, seeing that the highest office of the Roman commonwealth had remained at all times a kingship restricted by a number of special laws, the idea of the regal office itself had by no means become obsolete. At very various periods and from very different sides-- in the decemviral power, in the Sullan regency, and in Caesar's own dictatorship--there had been during the republic a practical recurrence to it; indeed by a certain logical necessity, whenever an exceptional power seemed requisite there emerged, in contradistinction to the usual limited -imperium-, the unlimited -imperium- which was simply nothing else than the regal power.
Lastly, outward considerations also recommended this recurrence to the former kingly position. Mankind have infinite difficulty in reaching new creations, and therefore cherish the once developed forms as sacred heirlooms. Accordingly Caesar very judiciously connected himself with Servius Tullius, in the same way as subsequently Charlemagne connected himself with Caesar, and Napoleon attempted at least to connect himself with Charlemagne. He did so, not in a circuitous way and secretly, but, as well as his successors, in the most open manner possible; it was indeed the very object of this connection to find a clear, national, and popular form of expression for the new state.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/5-11-old-republic-new-monarchy.asp?pg=39