According to Aristotle, _Pol_. v. 1311 b, he had previously killed
Xerxes' son Darius, and was afraid that the father would avenge him;
according to Ctesias, _Pers_. 29, Justin iii. 1, Diod. xi. 69, he killed
Xerxes first and then pretended that Darius had murdered him, and
instigated his brother Artaxerxes to avenge the parricide. At all
events, during the first months of the reign of Artaxerxes I., he was
the ruling power in the state (therefore the chronographers wrongly
reckon him as king, with a reign of seven months), until Artaxerxes,
having learned the truth about the murder of his father and his brother,
overwhelmed and killed Artabanus and his sons in open fight.