There was no politics in Persia because the great king was…

““There was no politics in Persia because the great king was the master of slaves, not rulers of citizens. The point is beautifully made by Herodotus, the father of history and our own starting point. The exiled Spartan king, Demaratus, had taken refuge at the court of the great king of Persia, Darius I, in 491 BCE. Darius made him the ruler of Pergamum and some other cities. In 480 Darius's son and successor, Xerxes, took him to see the enormous army he had assembled to avenge his father's humiliation by the Athenians in an earlier attempt to conquer Greece. 'Surely,' he said to Demaratus, "the Greeks will not fight against such odds.' He was displeased when Demaratus assured him that they certainly would. 'How is it possible that a thousand men-- or ten thousand, or fifty thousand should stand up to an army as big as mine, especially if they were not under a single master but all perfectly free to do as they pleased?' He could understand that they might feign courage if they were whipped into battle as his Persian troops would be, but it was absurd to suppose that they would fight against such odds. Not a bit of it, said Demaratus. THey would fight and die to preserve their freedom. He added, 'They are free--yes--but they are not wholly free; for they have a master, and that master is Law, which they fear much more than your subjects fear you. Whatever this master commands they do; and his command never varies: it is never to retreat in battle, however great the odds, but always to remain in formation and to conquer or die.' They were Citizens, not subjects, and free men, not slaves; they were disciplined but self-disciplined. Free men were not whipped into battle.””

— Alan Ryan