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 Pontic Proceedings in Greece
There Mithradates carried on his operations not only by arms, but at the same time by national propagandism. His chief instrument for Athens was one Aristion, by birth an Attic slave, by profession formerly a teacher of the Epicurean philosophy, now a minion of Mithradates; an excellent master of persuasion, who by the brilliant career which he pursued at court knew how to dazzle the mob, and with due gravity to assure them that help was already on the way to Mithradates from Carthage, which had been for about sixty years lying in ruins.
These addresses of the new Pericles were so far effectual that, while the few persons possessed of judgment escaped from Athens, the mob and one or two literati whose heads were turned formally renounced the Roman rule. So the ex-philosopher became a despot who, supported by his bands of Pontic mercenaries, commenced an infamous and bloody rule; and the Piraeeus was converted into a Pontic harbour. As soon as the troops of Mithradates gained a footing on the Greek continent, most of the small free states--the Achaeans, Laconians, Boeotians--as far as Thessaly joined them.
Sura, after having drawn some reinforcements from Macedonia, advanced into Boeotia to bring help to the besieged Thespiae and engaged in conflicts with Archelaus and Aristion during three days at Chaeronea; but they led to no decision and Sura was obliged to retire when the Pontic reinforcements from the Peloponnesus approached (end of 666, beg. of 667). So commanding was the position of Mithradates, particularly by sea, that an embassy of Italian insurgents could invite him to make an attempt to land in Italy; but their cause was already by that time lost, and the king rejected the suggestion.
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Reference address : https://www.ellopos.net/elpenor/rome/4-08-east-king-mithradates.asp?pg=47