But in the event it was not till after the reign of Sargon closed that Nineveh was made the definitive seat of the last Assyrian kings. Organized and strengthened during Tiglath Pileser's reign of eighteen years, this new imperial machine, with its standing professional army, its myriad levies drawn from all fighting races within its territory, its large and secure revenues and its bureaucracy keeping the provinces in constant relation to the centre, became the most tremendous power of offence which the world had seen. So soon as Assyria was made conscious of her new vigour by the ease with which the Urartu raiders, who had long been encroaching on Mesopotamia, and even on Syria, were driven back across the Nairi lands and penned into their central fastnesses of Van; by the ease, too, with which Babylonia was humbled and occupied again, and the Phoenician ports and the city of Damascus, impregnable theretofore, were taken and held to tribute--she began to dream of world empire, the first society in history to conceive this unattainable ideal. Certain influences and events, however, would defer awhile any attempt to realize the dream. Changes of dynasty took place, thanks partly to reactionary forces at home and more to the praetorian basis on which the kingdom now reposed, and only one of his house succeeded Tiglath Pileser. But the set-back was of brief duration. In the year 722 another victorious general thrust himself on to the throne and, under the famous name of Sargon, set forth to extend the bounds of the empire towards Media on the east, and over Cilicia into Tabal on the west, until he came into collision with King Mita of the Mushki and held him to tribute. SECTION 2. THE EMPIRE OF SARGON Though at least one large province had still to be added to the Assyrian Empire, Sargon's reign may be considered the period of its greatest strength. He handed on to Sennacherib no conquests which could not have been made good, and the widest extent of territory which the central power was adequate to hold. We may pause, then, just before Sargon's death in 705, to see what the area of that territory actually was.