Still, it will not be necessary to trace in detail the steps of the retreat. It was the fact of the return, rather than the mode of its accomplishment, which importantly affected the subsequent history of Persia. We need only note that the retreat was successfully conducted in spite, not merely of the military power of the Empire, but of the most barefaced and cruel treachery--a fact which showed clearly the strong desire that there was to hinder the invaders’ escape. Persia did not set much store by her honor at this period; but she would scarcely have pledged her word and broken it, without the slightest shadow of excuse, unless she had regarded the object to be accomplished as one of vast importance, and seen no other way which offered any prospect of the desired result. Her failure, despite the success of her treachery, places her military weakness in the strongest possible light. The Greeks, though deprived of their leaders, deceived, surprised, and hemmed in by superior numbers, amid terrific mountains, precipices, and snows, forced their way by sheer dogged perseverance through all obstacles, and reached Trebizond with the loss of not one fourth of their original number. There was also another discovery made during the return which partly indicated the weakness of the Persian power, and partly accounted for it. The Greeks had believed that the whole vast space enclosed between the Black Sea, Caucasus, Caspian, and Jaxartes on the one hand, and the Arabian Desert, Persian Gulf, and Indian Ocean on the other, was bound together into one single centralized monarchy, all the resources of which were wielded by a single arm. They now found that even towards the heart of the empire, on the confines of Media and Assyria, there existed independent tribes which set the arms of Persia at defiance; while towards the verge of the old dominion whole provinces, once certainly held in subjection, had fallen away from the declining State, and succeeded in establishing their freedom. The nineteenth satrapy of Herodotus existed no more; in lieu of it was a mass of warlike and autonomous tribes--Chalybes, Taochi, Chaldeans, Macronians, Scythians, Colchians, Mosynoecians, Tibarenians--whose services, if he needed them, the King of Persia had to buy, while ordinarily their attitude towards him was one of distrust and hostility. Judging of the unknown from the known, the Greeks might reasonably conclude that in all parts of the Empire similar defections had occurred, and that thus both the dimensions and the resources of the state had suffered serious diminution, and fell far below the conception which they had been accustomed to form of them.