Ariobarzanes, sometimes known as Ariobarzanes I of Cius, was a Persian Satrap of Phrygia and military commander, leader of an independence revolt, and the first known of the line of rulers of the Greek town of Cius who eventually were to stem the kings of Pontus in the 3rd century BCE. Ariobarzanes was apparently a cadet member of the Achaemenid dynasty, possibly son of Pharnabazus II, and part of the Pharnacid dynasty which had settled to hold Dascylium of Hellespont in the 470s BCE. Cius is located near Dascylium, and Cius seemingly was a share of family holdings for the branch of Ariobarzanes.

Pharnabazus II was a Persian soldier and statesman, and Satrap of Hellespontine Phrygia. He was the son of Pharnaces II of Phrygia and grandson of Pharnabazus I, and great-grandson of Artabazus I. He and his male ancestors, forming the Pharnacid dynasty, had governed the satrapy of Hellespontine Phrygia from its headquarters at Dascylium since 478 BC. He married Apama, daughter of Artaxerxes II of Persia, and their son Artabazus also became a satrap of Phrygia. According to some accounts, his granddaughter Barsine may have become Alexander the Great's concubine.