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
Political Abolition of the Patriciate
With the election of the first non-patrician consul--the choice fell on one of the authors of this reform, the late tribune of the people, Lucius Sextius Lateranus--the clan-aristocracy ceased both in fact and in law to be numbered among the political institutions of Rome.
When after the final passing of these laws the former champion of the clans, Marcus Furius Camillus, founded a sanctuary of Concord at the foot of the Capitol--upon an elevated platform, where the senate was wont frequently to meet, above the old meeting-place of the burgesses, the Comitium--we gladly cherish the belief that he recognized in the legislation thus completed the close of a dissension only too long continued.
The religious consecration of the new concord of the community was the last public act of the old warrior and statesman, and a worthy termination of his long and glorious career. He was not wholly mistaken; the more judicious portion of the clans evidently from this time forward looked upon their exclusive political privileges as lost, and were content to share the government with the plebeian aristocracy. In the majority, however, the patrician spirit proved true to its incorrigible character.
On the strength of the privilege which the champions of legitimacy have at all times claimed of obeying the laws only when these coincide with their party interests, the Roman nobles on various occasions ventured, in open violation of the stipulated arrangement, to nominate two patrician consuls. But, when by way of answer to an election of that sort for the year 411 the community in the year following formally resolved to allow both consular positions to be filled by non-patricians, they understood the implied threat, and still doubtless desired, but never again ventured, to touch the second consular place.
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Reference address : https://www.ellopos.net/elpenor/rome/2-03-equalization-orders-aristocracy.asp?pg=19