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
The district, which was mostly inhabited by old burgesses, joined him; the young men, many of whom had served with him under his father, readily ranged themselves under the courageous leader who, not yet twenty-three years of age, was as much soldier as general, sprang to the front of his cavalry in combat, and vigorously assailed the enemy along with them. The corps of Picenian volunteers soon grew to three legions; divisions under Cloelius, Gaius Carrinas, Lucius Junius Brutus Damasippus,(13) were despatched from the capital to put down the Picenian insurrection, but the extemporized general, dexterously taking advantage of the dissensions that arose among them, had the skill to evade them or to beat them in detail and to effect his junction with the main army of Sulla, apparently in Apulia.
13. We can only suppose this to be the Brutus referred to, since Marcus Brutus the father of the so-called Liberator was tribune of the people in 671, and therefore could not command in the field.
Sulla saluted him as -imperator-, that is, as an officer commanding in his own name and not subordinate but co-ordinate, and distinguished the youth by marks of honour such as he showed to none of his noble clients--presumably not without the collateral design of thereby administering an indirect rebuke to the lack of energetic character among his own partisans.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/4-09-cinna-sulla.asp?pg=34