It became necessary to decide this question before Darius's death; for Darius, in the prosecution of a war in which he was engaged, formed the design of accompanying his army on an expedition into Greece, and, before doing this, he was bound, according to the laws and usages of the Persian realm, to regulate the succession.
There immediately arose an earnest dispute between the friends and partisans of Artobazanes and Xerxes, each side urging very eagerly the claims of its own candidate. The mother and the friends of Artobazanes maintained that he was the oldest son, and, consequently, the heir. Atossa, on the other hand, contended that Xerxes was the grandson of Cyrus, and that he derived from that circumstance the highest possible hereditary rights to the Persian throne.
This was in some respects true, for Cyrus had been the founder of the empire and the legitimate monarch, while Darius had no hereditary claims. He was originally a noble, of high rank, indeed, but not of the royal line; and he had been designated as Cyrus's successor in a time of revolution, because there was, at that time, no prince of the royal family who could take the inheritance. Those, therefore, who were disposed to insist on the claims of a legitimate hereditary succession, might very plausibly claim that Darius's government had been a regency rather than a reign; that Xerxes, being the oldest son of Atossa, Cyrus's daughter, was the true representative of the royal line; and that, although it might not be expedient to disturb the possession of Darius during his lifetime, yet that, at his death, Xerxes was unquestionably entitled to the throne.
There was obviously a great deal of truth and justice in this reasoning, and yet it was a view of the subject not likely to be very agreeable to Darius, since it seemed to deny the existence of any real and valid title to the sovereignty in him. It assigned the crown, at his death, not to his son as such, but to his predecessor's grandson; for though Xerxes was both the son of Darius and the grandson of Cyrus, it was in the latter capacity that he was regarded as entitled to the crown in the argument referred to above. The doctrine was very gratifying to the pride of Atossa, for it made Xerxes the successor to the crown as her son and heir, and not as the son and heir of her husband. For this very reason it was likely to be not very gratifying to Darius. He hesitated very much in respect to adopting it. Atossa's ascendency over his mind, and her influence generally in the Persian court, was almost overwhelming, and yet Darius was very unwilling to seem, by giving to the oldest grandson of Cyrus the precedence over his own eldest son, to admit that he himself had no legitimate and proper title to the throne.