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
Caesar's Project of Codification
Such was the state of the law as Caesar found it. If he projected the plan for a new code, it is not difficult to say what were his intentions. This code could only comprehend the law of Roman burgesses, and could be a general code for the empire merely so far as a code of the ruling nation suitable to the times could not but of itself become general subsidiary law throughout the compass of the empire. In criminal law, if the plan embraced this at all, there was needed only a revision and adjustment of the Sullan ordinances. In civil law, for a state whose nationality was properly humanity, the necessary and only possible formal shape was to invest that urban edict, which had already spontaneously grown out of lawful commerce, with the security and precision of statute-law.
The first step towards this had been taken by the Cornelian law of 687, when it enjoined the judge to keep to the maxims set forth at the beginning of his magistracy and not arbitrarily to administer other law (108)--a regulation, which may well be compared with the law of the Twelve Tables, and which became almost as significant for the fixing of the later urban law as that collection for the fixing of the earlier.
108. Cf. V. V. Transpadanes
But although after the Cornelian decree of the people the edict was no longer subordinate to the judge, but the judge was by law subject to the edict; and though the new code had practically dispossessed the old urban law in judicial usage as in legal instruction--every urban judge was still free at his entrance on office absolutely and arbitrarily to alter the edict, and the law of the Twelve Tables with its additions still always outweighed formally the urban edict, so that in each individual case of collision the antiquated rule had to be set aside by arbitrary interference of the magistrates, and therefore, strictly speaking, by violation of formal law.
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Reference address : https://www.ellopos.net/elpenor/rome/5-11-old-republic-new-monarchy.asp?pg=173