According to research by Theodor Nöldeke, he was descended from Otanes, one of the associates of Darius in the murder of Smerdis. Pharnabazus is first recorded as satrap of this province in 413 BC, when, having received orders from Darius II of Persia to send in the outstanding tribute of the Greek cities on the Ionian coast, he, like Tissaphernes of Caria, entered into negotiations with Sparta and began a war with Athens. The conduct of the war was much hindered by the rivalry between the two satraps, of whom Pharnabazus was by far the more energetic and upright. After the war he came into conflict with the Spartan general, Lysander.