re only recent conquerors of older Sumerian-origined civilizations, were not. Although one hundred twenty years later Cyrus himself was to be admired as an "ideal king" by the Greek historiographer-adventurer Xenophon (430-354 B.C.) in the Cyropaedia, as a rule Greeks considered Persians to be "barbarian." Ionian Greeks chaffed under Persian overlordship, however much peace, protection and incentive to prosperous trade that entity provided.
Cyrus died by assassination: the dynasty he founded was characterized by similar transitions of leadership. The Persian conquerors soon fell into a decadent mode of god-king hegemony, a far cry from the vital warrior caste that had burst onto the scene originally. Cyrus' son Cambyses aimed south in his conquests, not west, conquering Egypt. By the time Cambyses died of self-inflicted wounds in 529 B.C., his successor and distant relative Darius I (ruled 522-486 B.C.) was using levies drawn from conquered lands - led, of course, by Persians. Darius was an administrator first, a "conqueror" second: he is credited with organizing the Persian Empire along relatively benevolent lines, providing peace and solid communications.
Scythian raiders from the empire's northern borders threatened that security, though, and Darius' first incursion into the European mainland was aimed at them, not at the Greeks. The apparent plan was for a Persian punitive force to cross from Ionian Greece into peninsular Greece, through the "semi-barbarian" regions of Thrace, and proceed north - across the Danube, around the Black Sea - to circle and surprise the Scythians from a direction they did not expect. This expedition occurred in 512 B.C. and it was generally regarded as ill-conceived. The Scythians refused to meet the Persians in open battle, but harassed Darius' army in what would now be considered classic guerilla warfare: quick hit-and-run attacks on the Persian flanks, on stragglers, and on supply lin...