He was the youngest child born to King Mithridates VI of Pontus from his first wife, his sister Queen Laodice.

The eastern part of Pontus remained under the rule of Pharnaces as a client kingdom until his death.

However, little is known of his youth from ancient writers and find him first mentioned after Mithridates VI was defeated by the Roman general Pompey during the Third Mithridatic War.

Cassius Dio and Florus wrote that Mithridates planned to attack Italy by crossing Scythia and the River Danube, according to the former, or through Thrace, Macedonia and the rest of Greece, according to the latter.

Mithridates suppressed this before it caused troubles and punished some people, including some of his sons, just of the basis of suspicions.

Pompey granted Pharnaces the kingdom of Bosporus and ‘enrolled him as a friend and ally’ of Rome.

[6] In contrast with Appian and Cassius Dio, Festus wrote that "Pompey imposed a king, Aristarchus, on the [Cimmerian] Bosphorians and Colchians.

He took advantage of the absence of Deiotarus, the king of Galatia and Lesser Armenia, to seize Lesser Armenia, part of Cappadocia, and some cities in the Roman province of Bithynia and Pontus which had formerly been part of the Kingdom of Pontus and had been assigned to the Bithynia district of that province.

He next advanced towards Bithynia and the Roman province of Asia, but stopped because he learnt that Asander, whom he had left in charge back home in the Cimmerian Bosporus had revolted.

[10] In his book on the Civil Wars, Appian only mentioned that Pharnaces seized the city of Amisus in Pontus, sold its inhabitants into slavery and made the boys eunuchs.

[12] Florus only mentioned Cappadocia and wrote that Pharnaces relied on Roman internal feuds rather that his valour to invade it.

King Deiotarus went to see to Calvinus to beg him not to allow Lesser Armenia or Cappadocia, to be overrun by Pharnaces, otherwise he could not pay the money he had promised to Caesar.

Domitius considered this money to be indispensable for the military expenses and felt that it would be shameful if the kingdoms of the Roman allies and friends were to be seized by Pharnaces.

Thus, he sent envoys to Pharnaces to ask him to withdraw from Armenia and Cappadocia, believing that this would have greater impact than advancing on him with an army.

Pharnaces occupied Pontus, took many towns by storm, plundered the property of Roman and Pontic citizens and meted out harsh punishments on the youth.

[16] Cassius Dio wrote that after escaping the siege of Alexandria and defeating Ptolemy XIII of Egypt, Caesar rushed to Armenia.

Pharnaces, who was heading north to deal with the rebellion of Asander, turned back to meet Caesar.

He hoped for a truce and that Caesar would proceed to deal with urgent matters in Italy and Africa, after which he could resume his war.

[17] According to Plutarch, Caesar learned about the defeat of Domitius by Pharnaces and that Pharnaces was taking advantage of this to occupy Bithynia and Cappadocia and hoped to gain Lesser Armenia by instigating revolts by the local princes and tetrarchs when he left Egypt and was crossing Asia.

This made victory easy as his men could throw darts at the enemy and put them to flight quickly.

[19] Appian wrote that when Caesar was within 200 stades (c. 3 km, 1.9 miles), Pharnaces sent envoys to negotiate peace.

Caesar wanted to quickly sort out affairs in Syria, Cilicia and Asia and deal with Pharnaces first.

Caesar replied that he would be fair if Pharnaces kept his promise and ordered him to withdraw from Pontus and make restitutions to Rome's allies and Roman citizens.

Pharnaces promised to comply and, hoping that Caesar would trust him as he had to return to Rome in a hurry, he asked for a later date for his withdrawal and proposed agreements as a delaying tactic.

Pharnaces had repaired the rampart of the camp his father had built when he posted his forces there during the Third Mithridatic War.

[21] In response, Julius Caesar gave a tetrarchy in Galatia and the title of king to Mithridates of Pergamon.

Caesar also allowed him to wage war against Asander and conquer the Cimmerian Bosporus because he had shown cruelty to his friend Pharnaces.

On the reverse, it displays Apollo semi-draped, seated on a lion-footed throne, holding a laurel branch over a tripod.

The names that Pharnaces II gave his children are a representation of his Persian and Greek heritage and ancestry.

His sons were made Pontic kings for a time after his death, by Roman triumvir Mark Antony.