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 king accordingly staked his whole personal weight to prevent things from taking this turn, and to induce the Armenian court to continue the war, in which he had nothing to lose and everything to gain; and, fugitive and dethroned as was Mithradates, his influence at this court was not slight. He was still a stately and powerful man, who, although already upwards of sixty years old, vaulted on horseback in full armour, and in hand-to-hand conflict stood his ground like the best.
Years and vicissitudes seemed to have steeled his spirit: while in earlier times he sent forth generals to lead his armies and took no direct part in war himself, we find him henceforth as an old man commanding in person and fighting in person on the field of battle. To one who, during his fifty years of rule, had witnessed so many unexampled changes of fortune, the cause of the great-king appeared by no means lost through the defeat of Tigranocerta; whereas the position of Lucullus was very difficult, and, if peace should not now take place and the war should be judiciously continued, even in a high degree precarious.
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Reference address : https://www.ellopos.net/elpenor/rome/5-02-rule-sullan-restoration.asp?pg=49