With his death, Persia sank back into the obscurity from which Cyrus had raised her rather more than two centuries previously.  With the exception of the Medes, none of the nations which had exercised the hegemony of the East before her time, not even Assyria, had had at their disposal such a wealth of resources and had left behind them so few traces of their power.  A dozen or so of palaces, as many tombs, a few scattered altars and stelae, remains of epics preserved by the Greeks, fragments of religious books, often remodelled, and issuing in the Avesta—­when we have reckoned up all that remains to us of her, what do we find to compare in interest and in extent with the monuments and wealth of writings bequeathed to us by Egypt and Chaldaea?  The Iranians received Oriental civilisation at a time when the latter was in its decline, and caught the spirit of decadence in their contact with it.  In succeeding to the patrimony of the nations they conquered, they also inherited their weakness; in a few years they had lost all the vigour of their youth, and were barely able to maintain the integrity of the empire they had founded.  Moreover, the great peoples to whom they succeeded, although lacking the vigour necessary for the continuance of their independent existence, had not yet sunk so low as to acquiesce in their own decay, and resign themselves to allowing their national life to be absorbed is that of another power:  they believed that they would emerge from the crisis, as they had done from so many others, with fresh strength, and, as soon as an occasion presented itself, they renewed the war against their Iranian suzerain.  Prom, the first to the latest of the sovereigns bearing the name of Darius, the history of the Achaemenids in an almost uninterrupted series of internal wars and provincial revolts.  The Greeks of Ionia, the Egyptians, Chaldaeans, Syrians, and the tribes of Asia Minor, all rose one after another, sometimes alone, sometimes in concert; some carrying on hostilities for not more than two or three years; others, like Egypt, maintaining them for more than half a century.  They were not discouraged by the reprisals which followed each of these rebellions; they again had recourse to arms as soon as there seemed the least chance of success, and they renewed the struggle till from sheer exhaustion the sword fell from their hand.  Persia was worn out by this perpetual warfare, in which at the same time each of her rivals expended the last relics of their vitality, and when Macedonia entered on the scene, both lords and vassals were reduced to such a state of prostration, that it was easy to foretell their approaching end.  The old Oriental world was in its death-throes; but before it passed away, the successful audacity of Alexander had summoned Greece to succeed to its inheritance.