Cyrus himself had still to deal with a part of the East which, not having been occupied by the Medes, though in a measure allied and subservient to them, saw no reason now to acknowledge the new dynasty. This is the part which had been included in the New Babylonian Empire. The Persian armies invaded Babylonia. Nabonidus was defeated finally at Opis in June 538; Sippara fell, and Cyrus' general appearing before Babylon itself received it without a struggle at the hands of the disaffected priests of Bel-Marduk. The famous Herodotean tale of Cyrus' secret penetration down the dried bed of Euphrates seems to be a mistaken memory of a later recapture of the city after a revolt from Darius, of which more hereafter. Thus once more it was given to Cyrus to close a long chapter of Eastern history--the history of imperial Babylon. Neither did he make it his capital, nor would any other lord of the East so favour it. If Alexander perhaps intended to revive its imperial position, his successor, Seleucus, so soon as he was assured of his inheritance, abandoned the Euphratean city for the banks of the Tigris and Orontes, leaving it to crumble to the heap which it is to-day.
The Syrian fiefs of the Babylonian kings passed _de jure_ to the conqueror; but probably Cyrus himself never had leisure or opportunity to secure them _de facto_. The last decade of his life seems to have been spent in Persia and the north-east, largely in attempts to reduce the Scythian element, which threatened the peace of Media; and at the last, having brought the enemy to bay beyond the Araxes, he met there defeat and death. But Cambyses not only completed his father's work in Syria, but fulfilled what is said to have been his further project by capturing Egypt and establishing there a foreign domination which was to last, with some intervals, nearly two hundred years. By the end of the sixth century one territorial empire was spread over the whole East for the first time in history; and it was with a colossus, bestriding the lands from the Araxes to the Upper Nile and from the Oxus to the Aegean Sea, that the Greeks stood face to face in the gate of the West.
Before, however, we become absorbed in contemplation of a struggle which will take us into a wider history, let us pause a moment to consider the nature of the new power come out of the East, and the condition of such of its subject peoples as have mattered most in the later story of mankind. It should be remarked that the new universal power is not only non-Semitic for the first time in well-certified history, but controlled by a very pure Aryan stock, much nearer kin to the peoples of the West than any Oriental folk with which they have had intimate relations hitherto. The Persians appeared from the Back of Beyond, uncontaminated by Alarodian savagery and unhampered by the theocratic prepossessions and nomadic traditions of Semites. They were highlanders of unimpaired vigour, frugal habit, settled agricultural life, long-established social cohesion and spiritual religious conceptions. Possibly, too, before they issued from the vast Iranian plateau, they were not wholly unversed in the administration of wide territories. In any case, their quick intelligence enabled them to profit by models of imperial organization which persisted in the lands they now acquired; for relics of the Assyrian system had survived under the New Babylonian rule, and perhaps also under the Median. Thereafter the experience gained by Cambyses in Egypt must have gone for something in the imperial education of his successor Darius, to whom historians ascribe the final organization of Persian territorial rule. From the latter's reign onward we find a regular provincial system linked to the centre as well as might be by a postal service passing over state roads. The royal power is delegated to several officials, not always of the ruling race, but independent of each other and directly responsible to Susa: these live upon their provinces but must see to it first and foremost that the centre receives a fixed quota of money and a fixed quota of fighting men when required. The Great King maintains royal residences in various cities of the empire, and not infrequently visits them; but in general his viceroys are left singularly free to keep the peace of their own governorates and even to deal with foreign neighbours at their proper discretion.