(M728) It was to overthrow this empire that Philip aspired, after he had conquered Greece, in part to revenge the injuries inflicted by the Persian invasions, but more from personal ambition. And had he lived, he would have succeeded, and his name would have been handed down as the great conqueror, rather than that of his more fortunate son. Philip knew what a rope of sand the Persian military power was. Xenophon had enlightened the Greeks as to the inefficiency of the Persian armies, if they needed any additional instruction after the defeat of Xerxes and his generals. The vast armies of the Persians made a grand show, and looked formidable when reviewed by the king in his gilded chariot, surrounded by his nobles, the princes of his family, and the women of his harem. And these armies were sufficient to keep the empire together. The mighty prestige attending victories for one thousand years, and all the pomp of millions in battle array, was adequate to keep the province together, for the system of warfare and the character of the forces were similar in all the provinces. It was external enemies, with a different system of warfare, that the Persian kings had to dread—not the revolt of enervated States, and unwarlike cities. The Orientals were never warlike in the sense that Greece and Rome were. The armies of Greece and Rome were small, but efficient. It was seldom that any Grecian or Roman army exceeded fifty thousand men, but they were veterans, and they had military science and skill and discipline. The hosts of Xerxes or Darius were undisciplined, and they were mercenaries, unlike the original troops of Cyrus.