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
Invasion of Pontus by Lucullus
Lucullus now in turn proceeded to the aggressive. Triarius received the command of the fleet, with orders first of all to blockade the Hellespont and lie in wait for the Pontic ships returning from Crete and Spain; Cotta was charged with the siege of Heraclea; the difficult task of providing supplies was entrusted to the faithful and active princes of the Galatians and to Ariobarzanes king of Cappadocia; Lucullus himself advanced in the autumn of 681 into the favoured land of Pontus, which had long been untrodden by an enemy. Mithradates, now resolved to maintain the strictest defensive, retired without giving battle from Sinope to Amisus, and from Amisus to Cabira (afterwards Neocaesarea, now Niksar) on the Lycus, a tributary of the Iris; he contented himself with drawing the enemy after him farther and farther into the interior, and obstructing their supplies and communications.
Lucullus rapidly followed; Sinope was passed by; the Halys, the old boundary of the Roman dominion, was crossed and the considerable towns of Amisus, Eupatoria (on the Iris), and Themiscyra (on the Thermodon) were invested, till at length winter put an end to the onward march, though not to the investments of the towns. The soldiers of Lucullus murmured at the constant advance which did not allow them to reap the fruits of their exertions, and at the tedious and--amidst the severity of that season-- burdensome blockades.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/5-02-rule-sullan-restoration.asp?pg=35