In the political convulsions through which she had passed, Greek soldiers had often been used by her contending chiefs.

These military operations were attended by a momentous result.

They revealed, to the quick eye of these warlike mercenaries, the political weakness of the empire and the possibility of reaching its centre.

After the death of Cyrus on the battle-field of Cunaxa, it was demonstrated, by the immortal retreat of the ten thousand under Xenophon, that a Greek army could force its way to and from the heart of Persia.
That reverence for the military abilities of Asiatic generals, so profoundly impressed on the Greeks by such engineering exploits as the bridging of the Hellespont, and the cutting of the isthmus at Mount Athos by Xerxes, had been obliterated at Salamis, Platea, Mycale.

To plunder rich Persian provinces had become an irresistible temptation.
Such was the expedition of Agesilaus, the Spartan king, whose brilliant successes were, however, checked by the Persian government resorting to its time-proved policy of bribing the neighbors of Sparta to attack her.
"I have been conquered by thirty thousand Persian archers," bitterly exclaimed Agesilaus, as he re-embarked, alluding to the Persian coin, the Daric, which was stamped with the image of an archer.
THE INVASION OF PERSIA BY GREECE.