The dominion of the princes under which the Medes stood is followed by the dominion of the monarchy, which must have arisen out of it. One of the families of these princes must have succeeded in obtaining influence and power over the others. The position of Deioces and Phraortes must have arisen and developed itself in this manner. Whether the Dayauku, whom Sargon carried off in the year 715 B.C. with his followers to Amat, is one and the same person with the prince of Bit Dayauku, against whom the Assyrian king marched in the year 713 B.C. (p. 282), would be difficult to decide; and even if the matter could be determined with certainty, it would not be of great importance. We often find the kings of Asshur replacing conquered and captive princes in their dominions. On the other hand, it is of importance that there was a region of Media, which could be called Bit Dayauku, _i.e._ the land of Dayauku, by the Assyrians in the year 713 B.C. There must have existed at this time a principality of Deioces among other principalities, and the beginning of this must be put earlier than the date allowed by Herodotus for the election, _i.e._ at the latest at 720 B.C. In course of time the land of Deioces may have increased in extent, and the importance of the ruler may have grown--though he may not, after the conflict of 713 B.C., have taken any leading part in the resistance to the payment of tribute, the conflicts and successes of other chieftains against the Assyrians; at any rate, there is no subsequent mention of the land in the inscriptions. Neither Deioces nor his land is mentioned when Sennacherib speaks of the tribute of the whole of Media, and the subjugation of the country under his dominion; nor even when Esarhaddon speaks of the conquest of the most distant princes. Hence we can only grant to the narrative of Herodotus that, in the times of Sennacherib and Esarhaddon, Deioces, the son of Phraortes, had a considerable territory among the chiefs of the Medes, and greater importance than others, and we have no reason to look for his dominion elsewhere than at Ecbatana. His son Phraortes (Fravartis), who according to Herodotus came to the throne in the year 655 B.C., must have succeeded in uniting the chiefs of the Medes under his sway, and combining with the tribes of the Persians, among whom at that time the race of the Achæmenids had acquired a prominent position,[479] in order to maintain their independence against Assyria.