Artabanus probably originated from the province of Hyrcania and reportedly served as the chief official of Xerxes I.
On the other hand, Junianus Justinus reported that Artabanus had personal ambitions for the throne.
He first secretly murdered Xerxes and then accused Darius of parricide, resulting in his execution.
The order of events remains uncertain but the deaths of Xerxes and Darius did leave the throne vacant.
Others consider him to have named young Artaxerxes I as King and to have acted as Regent and power behind the throne.