Mithridates IV of Pontus is first mentioned in 179 BCE in association with Pharnaces I in a treaty concluded by the latter King of Pergamon, Eumenes II, in a manner that would lead one to suppose he was already admitted to some share in sovereign power.

The date of Mithridates’ accession to the Pontian throne is utterly mysterious, since we first hear of him as ruler in 154 BCE, when he is mentioned as sending an auxiliary force to the assistance of King of Pergamon, Attalus II Philadelphus, against the King of Bithynia, Prusias II.

This moment is an important event, since it signals the start of a policy of friendship of the Kingdom of Pontus with the Roman Republic and her allies that is to continue until the time of Mithridates VI Eupator.