Although only his books on the Roman Civil Wars survive in their entirety, large parts of other books have also come down to us. Fortunately, the Mithridatic Wars, about Rome's struggle with the kingdom of Pontus, belong to these better preserved parts. They are a very valuable source for the history of the Roman expansion in what is now called Turkey.
The translation was made by Horace White; notes by Jona Lendering.
 Pompey then passed over Mount Taurus and made war against Antiochus, the king of Commagene, until the latter entered into friendly relations with him.note[64 BCE.] He also fought against Darius the Mede, and put him to flight, either because he had helped Antiochus, or Tigranes before him.
He made war against the Nabataean Arabs, whose king was Aretas, and against the Jews (whose king, Aristobulus, had revolted), until he had captured their holiest city, Jerusalem.note[In 63 BCE; more....]
He advanced against, and brought under Roman rule without fighting, those parts of Cilicia that were not yet subject to it, and the remainder of Syria which lies along the Euphrates, and the countries called Coele Syria, Phoenicia, and Palestine, also Idumea and Ituraea, and the other parts of Syria by whatever name called; not that he had any complaint against Antiochus, the son of Antiochus Pius, who was present and asked for his paternal kingdom, but because he thought that since henote[Pompey.] had dispossessed Tigranes,note[The Armenian king Tigranes the Great.] the conqueror of Antiochus, it belonged to the Romans by the law of war.
While he was settling these affairs ambassadors came to him from Phraates and Tigranes, who had gone to war with each other. Those of Tigranes asked the aid of Pompey as an ally, while those of the Parthian sought to secure for him the friendship of the Roman people. As Pompey did not think it best to fight the Parthians without a decree of the Senate, he sent mediators to compose their differences.
 While Pompey was about this business Mithridates had completed his circuit of the Euxine and occupied Panticapaeum, a European market town at the outlet of that sea. There at the Bosphorus he put to death Xiphares, one of his sons, on account of the following fault of his mother.
Mithridates had a castle where, in a secret underground treasury, a great deal of money lay concealed in numerous iron-bound brazen vessels. Stratonice, one of the king's concubines or wives, had been put in charge of this castle, and while he was still making his journey around the Euxine she delivered it up to Pompey and revealed to him the secret treasures, on the sole condition that he should spare her son, Xiphares, if he should capture him. Pompey took the money and promised her that he would spare Xiphares, and allowed her to take away her own things.
When Mithridates learned these facts he killed Xiphares at the straits, while his mother was looking on from the opposite shore, and cast his body out unburied, thus wreaking his spite on the son in order to grieve the mother who had offended him.
And now he sent ambassadors to Pompey, who was still in Syria and who did not know that the king was at that place. They promised that the king would pay tribute to the Romans if they would let him have his paternal kingdom. When Pompey required that Mithridates should come himself and make his petition as Tigranes had done, he said that as long as he was Mithridates he would never agree to that, but that he would send some of his sons and his friends to do so. Even while he was saying these things he was levying an army of freedmen and slaves promiscuously, manufacturing arms, projectiles, and machines, helping himself to timber, and killing plough-oxen for the sake of their sinews. He levied tribute on all, even those of the slenderest means. His ministers made these exactions with harshness to many, without his knowledge, for he had fallen sick with ulcers on his face and allowed himself to be seen only by three eunuchs, who cured him.
 When he had recovered from his illness and his army was collected (it consisted of sixty picked cohorts of 6,000 men each and a great multitude of other troops, besides ships and strongholds that had been captured by his generals while he was sick) he sent a part of it across the strait to Phanagoria, another trading place at the mouth of the sea, in order to possess himself of the passage on either side while Pompey was still in Syria.
Castor of Phanagoria, who had once been maltreated by Trypho, the king's eunuch, fell upon the latter as he was entering the town, killed him, and summoned the citizens to revolt. Although the citadel was already held by Artaphernes and other sons of Mithridates, the inhabitants piled wood around it and set it on fire, in consequence of which Artaphernes, Darius, Xerxes, and Oxathres, sons, and Eupatra, a daughter, of Mithridates, in fear of the fire, surrendered themselves and were led into captivity. Of these Artaphernes alone was about forty years of age; the others were handsome children.
Cleopatra, another daughter, resisted. Her father, in admiration of her courageous spirit, sent a number of row-boats and rescued her.
All the neighboring castles that had been lately occupied by Mithridates now revolted from him in emulation of the Phanagoreans, namely, Chersonesus, Theodosia, Nymphaeum, and others around the Euxine which were well situated for purposes of war. Mithridates, observing these frequent defections, and having suspicions of the army itself, lest it should fail him because the service was compulsory and the taxes very heavy, and because soldiers always lack confidence in unlucky commanders, sent some of his daughters in charge of eunuchs to be married to the Scythian princes, asking them at the same time to send him reinforcements as quickly as possible. Five hundred soldiers accompanied them from his own army. Soon after they left the presence of Mithridates they killed the eunuchs who were leading them (for they always hated these persons, who were all-powerful with Mithridates) and conducted the young women to Pompey.
 Although bereft of so many children and castles and of his whole kingdom, and in no way fit for war, and although he could not expect any aid from the Scythians, still no inferior position, none corresponding to his present misfortunes, even then found a place in his mind. He proposed to turn his course to the Gauls, whose friendship he had cultivated a long time for this purpose, and with them to invade Italy, hoping that many of the Italians themselves would join him on account of their hatred of the Romans; for he had heard that such had been Hannibal's policy after the Romans had waged war against him in Spain, and that he had become in this way an object of the greatest terror to them.
He knew that almost all of Italy had lately revolted from the Romans by reason of their hatred and had waged war against them for a very long time, and had sustained Spartacus, the gladiator, against them, although he was a man of no repute.
Filled with these ideas he was for hastening to the Gauls, but his soldiers, though the very bold enterprise might be attractive, were deterred chiefly by its magnitude, and by the long distance of the expedition in foreign territory, against men whom they could not overcome even in their own country. They thought also that Mithridates, in utter despair, wanted to end his life in a valiant and kingly way rather than in idleness. So they tolerated him and remained silent, for there was nothing mean or contemptible about him even in his misfortunes.
 While affairs were in this plight Pharnaces, the son whom he was most fond of and whom he had often designated as his successor, either alarmed about the expedition and the kingdom (for he still had hopes of pardon from the Romans, but reckoned that he should lose everything completely if his father should invade Italy), or spurred by other motives, formed a conspiracy against his father.
His fellow conspirators were captured and put to the torture, but Menophanes persuaded the king that it would not be seemly, just as he was starting on his expedition, to put to death the son who had been until then the dearest to him. People were liable to such turns, he said, in time of war, and when they came to an end things quieted down again. In this way Mithridates was persuaded to pardon his son, but the latter, still fearing his father's anger, and knowing that the army shrank from the expedition, went by night to the leading Roman deserters who were encamped very near the king, and by representing to them in its true light, and as they well knew it, the danger of their advancing against Italy, and by making them many promises if they would refuse to go, induced them to desert from his father.
After Pharnaces had persuaded them, he sent emissaries the same night to other camps near by and won them over. Early in the morning the first deserters raised a shout, and those next to them repeated it, and so on. Even the naval force joined in the cry, not all of them having been advised beforehand perhaps, but eager for a change, despising failure, and always ready to attach themselves to a new hope. Others, who were ignorant of the conspiracy, thought that all had been corrupted, and that if they remained alone they would be scorned by the majority, and so from fear and necessity rather than inclination joined in the shouting.
Mithridates, being awakened by the noise, sent messengers out to inquire what the shouters wanted. The latter made no concealment, but said, "We want your son to be king; we want a young man instead of an old one who is ruled by eunuchs, the slayer of so many of his sons, his generals, and his friends."