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
While these rhetorical and political writings of Cicero with a philosophic colouring are not devoid of merit, the compiler on the other hand completely failed, when in the involuntary leisure of the last years of his life (709-710) he applied himself to philosophy proper, and with equal peevishness and precipitation composed in a couple of months a philosophical library. The receipt was very simple. In rude imitation of the popular writings of Aristotle, in which the form of dialogue was employed chiefly for the setting forth and criticising of the different older systems, Cicero stitched together the Epicurean, Stoic, and Syncretist writings handling the same problem, as they came or were given to his hand, into a so-called dialogue.
And all that he did on his own part was, to supply an introduction prefixed to the new book from the ample collection of prefaces for future works which he had beside him; to impart a certain popular character, inasmuch as he interwove Roman examples and references, and sometimes digressed to subjects irrelevant but more familiar to the writer and the reader, such as the treatment of the deportment of the orator in the -De Officiis-; and to exhibit that sort of bungling, which a man of letters, who has not attained to philosophic thinking or even to philosophic knowledge and who works rapidly and boldly, shows in the reproduction of dialectic trains of thought. In this way no doubt a multitude of thick tomes might very quickly come into existence--"They are copies," wrote the author himself to a friend who wondered at his fertility; "they give me little trouble, for I supply only the words and these I have in abundance." Against this nothing further could be said; but any one who seeks classical productions in works so written can only be advised to study in literary matters a becoming silence.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/5-12-religion-culture-literature-art.asp?pg=88