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
Feudatory Kings - Cappadocia - Commagene - Galatia
The first place, in rank at least, among the dependent dynasts was held by the king of Cappadocia, whose territory Lucullus had already enlarged by investing him with the province of Melitene (about Malatia) as far as the Euphrates, and to whom Pompeius farther granted on the western frontier some districts taken off Cilicia from Castabala as far as Derbe near Iconium, and on the eastern frontier the province of Sophene situated on the left bank of the Euphrates opposite Melitene and at first destined for the Armenian prince Tigranes; so that the most important passage of the Euphrates thus came wholly into the power of the Cappadocian prince.
The small province of Commagene between Syria and Cappadocia with its capital Samosata (Samsat) remained a dependent kingdom in the hands of the already-named Seleucid Antiochus;(21) to him too were assigned the important fortress of Seleucia (near Biradjik) commanding the more southern passage of the Euphrates, and the adjoining tracts on the left bank of that river; and thus care was taken that the two chief passages of the Euphrates with a corresponding territory on the eastern bank were left in the hands of two dynasts wholly dependent on Rome.
21. The war which this Antiochus is alleged to have waged with Pompeius (Appian, Mithr. 106, 117) is not very consistent with the treaty which he concluded with Lucullus (Dio, xxxvi. 4), and his undisturbed continuance in his sovereignty; presumably it has been concocted simply from the circumstance, that Antiochus of Commagene figured among the kings subdued by Pompeius.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/5-04-pompeius-east.asp?pg=51