They were not Darius' only pupils: during the reign of Xerxes, the Athenians, those archenemies of Persia, had started to copy several institutions invented by Darius, which is probably the ultimate compliment.
Cambyses died in Syria, without children, leaving the army without commander and the empire to Smerdis - or someone who resembled him. When Cambyses had departed into Egypt, the people became hostile, and the lie multiplied in the land, even in Persia and Media, and in the other provinces.
Artistic conventions, however, suggest a much earlier date.
These skills that Ahuramazda set down upon me. Inafter subduing eastern Thrace and the Getae, he crossed the Danube River into European Scythia, but the Scythian nomads devastated the country as they retreated from him, and he was forced, for lack of supplies, to abandon the campaign.
When Cambyses was in Egypt, during the last year of his reign, a certain Gaumata usurped the throne by pretending to be Bardiya, Cambyses' brother, who had been assassinated secretly before Cambyses started out for his Egyptian campaign in BCE.
Of wrong I am not a friend. While the punishments may seem brutal today, ranging from mutilation to blinding, fairness was not omitted as punishment depended on the nature and severity of the crime.