Polymnia   

The Seventh Book, Entitled
POLYMNIA

Now when tidings of the battle that had been fought at Marathon
reached the ears of King Darius, the son of Hystaspes, his anger
against the Athenians, which had been already roused by their attack
upon Sardis, waxed still fiercer, and he became more than ever eager
to lead an army against Greece. Instantly he sent off messengers to
make proclamation through the several states that fresh levies were to
be raised, and these at an increased rate; while ships, horses,
provisions, and transports were likewise to be furnished. So the men
published his commands; and now all Asia was in commotion by the space
of three years, while everywhere, as Greece was to be attacked, the
best and bravest were enrolled for the service, and had to make
their preparations accordingly.
After this, in the fourth year, the Egyptians whom Cambyses had
enslaved revolted from the Persians; whereupon Darius was more hot for
war than ever, and earnestly desired to march an army against both
adversaries.
Now, as he was about to lead forth his levies against Egypt and
Athens, a fierce contention for the sovereign power arose among his
sons; since the law of the Persians was that a king must not go out
with his army, until he has appointed one to succeed him upon the
throne. Darius, before he obtained the kingdom, had had three sons
born to him from his former wife, who was a daughter of Gobryas;
while, since he began to reign, Atossa, the daughter of Cyrus, had
borne him four. Artabazanes was the eldest of the first family, and
Xerxes of the second. These two, therefore, being the sons of
different mothers, were now at variance. Artabazanes claimed the crown
as the eldest of all the children, because it was an established
custom all over the world for the eldest to have the pre-eminence;
while Xerxes, on the other hand, urged that he was sprung from Atossa,
the daughter of Cyrus, and that it was Cyrus who had won the
Persians their freedom.
Before Darius had pronounced on the matter, it happened that
Demaratus, the son of Ariston, who had been deprived of his crown at
Sparta, and had afterwards, of his own accord, gone into banishment,
came up to Susa, and there heard of the quarrel of the princes.
Hereupon, as report says, he went to Xerxes, and advised him, in
addition to all that he had urged before, to plead- that at the time
when he was born Darius was already king, and bore rule over the
Persians; but when Artabazanes came into the world, he was a mere
private person. It would therefore be neither right nor seemly that
the crown should go to another in preference to himself. "For at
Sparta," said Demaratus, byway of suggestion, "the law is that if a
king has sons before he comes to the throne, and another son is born
to him afterwards, the child so born is heir to his father's kingdom."
Xerxes followed this counsel, and Darius, persuaded that he had
justice on his side, appointed him his successor. For my own part I
believe that, even without this, the crown would have gone to
Xerxes; for Atossa was all-powerful.
Darius, when he had thus appointed Xerxes his heir, was minded
to lead forth his armies; but he was prevented by death while his
preparations were still proceeding. He died in the year following
the revolt of Egypt and the matters here related, after having reigned
in all six-and-thirty years, leaving the revolted Egyptians and the
Athenians alike unpunished. At his death the kingdom passed to his son
Xerxes.
Now Xerxes, on first mounting the throne, was coldly disposed
towards the Grecian war, and made it his business to collect an army
against Egypt. But Mardonius, the son of Gobryas, who was at the
court, and had more influence with him than any of the other Persians,
being his own cousin, the child of a sister of Darius, plied him
with discourses like the following:-