Cyrus, Darius, Xerxes.
No.
Darius organized the empire by dividing it into 20 provinces.
Darius put down several revolts. He won more land for the empire and created a government for the empire !
Persia had a king, not an emperor. The Persian king Darius I was at home in Persia when the battle of Marathon took place, so he was not killed at Marathon. Darius the Great died of natural causes 14 years after Marathon.
Persia.
Cyrus, Darius, Xerxes.
Hystapses.
No.
Xerxes mother was Atossa, Darius I of Persia wife and Cyrus the Greats' daughter.
There were several Persian leaders called Darius - they were kings of Persia.
Darius organized the empire by dividing it into 20 provinces.
They were kings of Persia.
The King of Persia defeated by Alexander was Darius. After losing the battle of Gaugamela Darius was murdered by his own nobles.
Darius organized the empire by dividing it into 20 provinces.
Darius the Great.
Darius I enforced the coinage system which was adopted from Lydia (which was already conquered by Persia during that time). For more information you can look here: http://www.snible.org/coins/hn/persia.html or search "Persian coinage"