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
This had its effect; the legions rallied and vanquished the enemy's horse, after which the infantry were overthrown with little difficulty. On the following day the camp of the Asiatics was surrounded and stormed; far the greatest portion of them fell or perished in the Copaic marshes; a few only, Archelaus among the rest, reached Euboea. The Boeotian communities had severely to pay for their renewed revolt from Rome, some of them even to annihilation.
Nothing opposed the advance into Macedonia and Thrace; Philippi was occupied, Abdera was voluntarily evacuated by the Pontic garrison, the European continent in general was cleared of the enemy. At the end of the third year of the war (669) Sulla was able to take up winter-quarters in Thessaly, with a view to begin the Asiatic campaign in the spring of 670,(15) for which purpose he gave orders to build ships in the Thessalian ports.
15. The chronology of these events is, like all their details, enveloped in an obscurity which investigation is able to dispel, at most, only partially. That the battle of Chaeronea took place, if not on the same day as the storming of Athens (Pausan, i. 20), at any rate soon afterwards, perhaps in March 668, is tolerably certain. That the succeeding Thessalian and the second Boeotian campaign took up not merely the remainder of 668 but also the whole of 669, is in itself probable and is rendered still more so by the fact that Sulla's enterprises in Asia are not sufficient to fill more than a single campaign. Licinianus also appears to indicate that Sulla returned to Athens for the winter of 668-669 and there took in hand the work of investigation and punishment; after which he relates the battle of Orchomenus. The crossing of Sulla to Asia has accordingly been placed not in 669, but in 670.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/4-08-east-king-mithradates.asp?pg=59