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.
 Attalusnote[King Attalus II Philadelphus of Pergamon; in 149 BCE.] received the young man warmly and ordered Prusias to assign certain towns for his occupation, and territory to furnish him supplies. Prusias replied that he would presently give his son the whole kingdom of Attalus, which he had intended for Nicomedes when he invaded Asia before.
After giving this answer he made a formal accusation at Rome against Nicomedes and Attalus and cited them to trial. The forces of Attalus at once made an incursion into Bithynia, the inhabitants of which gradually took sides with the invaders. Prusias, trusting nobody and hoping that the Romans would rescue him from the toils of the conspiracy, asked and obtained from his son-in-law, Diegylis the Thracian, 500 men, and with these alone as a bodyguard he took refuge in the citadel of Nicaea.
The Roman praetor, in order to favor Attalus, delayed introducing the ambassadors of Prusias to the Senate at Rome. When he did introduce them, the Senate voted that the praetor himself should choose legates and send them to settle the difficulty. He selected three men, one of whom had once been struck on the head with a stone, from which he was badly scarred; another was a diseased cripple, and the third was considered almost a fool; wherefore Catonote[Marcus Porcius Cato.] made the contemptuous remark concerning this embassy, that it had no understanding, no feet and no head.
 The legates proceeded to Bithynia and ordered that the war be discontinued. Nicomedes and Attalus pretended to acquiesce. The Bithynians had been instructed to say that they could no longer endure the cruelty of Prusias, especially after they had openly complained against him. On the pretext that these complaints were not yet known at Rome the legates adjourned, leaving the business unfinished.
When Prusias despaired of assistance from the Romans (in reliance upon whom he had neglected to provide means for his own defense) he retired to Nicomedia in order to possess himself of the city and resist the invaders. The inhabitants, however, betrayed him and opened the gates, and Nicomedes entered with his army. Prusias fled to the temple of Zeus, where he was stabbed by some of the emissaries of Nicomedes.
In this way Nicomedes succeeded Prusias as king of the Bithynians. At his death his son, Nicomedes, surnamed Philopator,note[In fact this was the surname of the next Nicomedes.] succeeded him, the Senate confirming his ancestral authority. So much for Bithynia. To anticipate the sequel, another Nicomedes, grandson of this one, left the kingdom to the Romans in his will.note[Nicomedes IV bequeathed Bithynia to the Romans in 74. This was the immediate cause of the Third Mithridatic War.]
 Who were the rulers of Cappadocia before the Macedonians I am not able to say exactly - whether it had a government of its own or was subject to Darius.note[Persian king Darius I the Great.] I judge that Alexander left behind him governors of the conquered nations to collect the tribute while he hastened after Darius.note[Darius III Codomannus.] But it appears that he restored to Amisus, a city of Pontus, of Attic origin, its original democratic form of government. Yet Hieronymus says that he did not touch those nations at all, but that he went after Darius by another road, along the seacoast of Pamphylia and Cilicia.
But Perdiccas, who ruled the Macedonians after Alexander, captured and hanged Ariarathes, the governor of Cappadocia, either because he had revolted or in order to bring that country under Macedonian rule, and placed Eumenes of Cardia over these peoples. Eumenes was afterward adjudged an enemy of Macedonia and put to death, and Antipater, who succeeded Perdiccas as overseer of the territory of Alexander, appointed Nicanor satrap of Cappadocia.
 Not long afterward dissensions broke out among the Macedonians. Antigonus expelled Laomedon from Syria and assumed the government himself. He had with him one Mithridates, a scion of the royal house of Persia. Antigonus had a dream that he had sowed a field with gold, and that Mithridates reaped it and carried it off to Pontus. He accordingly arrested him, intending to put him to death, but Mithridates escaped with six horsemen, fortified himself in a stronghold of Cappadocia, where many joined him in consequence of the decay of the Macedonian power, and possessed himself of the whole of Cappadocia and of the neighboring countries along the Euxine.note[Mithridates I, surnamed Ktistes, "founder", was a member of a local branch of the Achaemenid royal family, and gained independence in the crisis after 302, which culminated in the Battle of Ipsus and the end of Antigonus Monophthalmus.]
This great power, which he had built up, he left to his children.note[266/265 BCE.] They reigned one after another until the sixth Mithridates in succession from the founder of the house, and he went to war with the Romans. Since there were kings of this house of both Cappadocia and Pontus, I judge that they divided the government, some ruling one country and some the other.
 At any rate a king of Pontus, the Mithridates surnamed Euergetes,note["Benefactor".] who was the first of them inscribed as a friend of the Roman people, and who even sent some ships and a small force of auxiliaries to aid them against the Carthaginians,note[During the Third Punic War (149-146).] invaded Cappadocia as though it were a foreign country.
He was succeeded by his son, Mithridates, surnamed Dionysus, and also Eupator. The Romans ordered him to restore Cappadocia to Ariobarzanes, who had fled to them and who seemed to have a better title to the government of that country than Mithridates; or perhaps they distrusted the growing power of that great monarchy and thought it would be better to have it divided into several parts.
Mithridates obeyed the order, but he put an army at the service of Socrates, surnamed Chrestus, the brother of Nicomedes, king of Bithynia, who overthrew the latter and usurped the government. (This Nicomedes was the son of Nicomedes the son of Prusias, who had received the kingdom of Bithynia as his patrimony at the hands of the Romans.)
Simultaneously Mithraas and Bagoas drove out Ariobarzanes, whom the Romans had confirmed as king of Cappadocia, and installed Ariarathes in his place.note[90 BCE.]