Each king, or period, in Herodotus occurs in the list of Ctesias twice--a transparent device, clumsily cloaked by the cheap expedient of a liberal invention of names.

Even the list of Herodotus requires curtailment.

His Deioces, whose whole history reads more like romance than truth--the organizer of a powerful monarchy in Media just at the time when Sargon was building his fortified posts in the country and peopling with his Israelite captives the old "cities of the Medes"-- the prince who reigned for above half a century in perfect peace with his neighbors, and who, although contemporary with Sargon, Sennacherib, Esar-haddon, and As-shur-bani-pal--all kings more or less connected with Media--is never heard of in any of their annals, must be relegated to the historical limbo in which repose so many "shades of mighty names;" and the Herodotean list of Median kings must at any rate, be thus far reduced.

Nothing is more evident than that during the flourishing period of Assyria under the great Sargonidae above named there was no grand Median kingdom upon the eastern flank of the empire.
Such a kingdom had certainly not been formed up to B.C.671, when Esar-haddon reduced the more distant Medes, finding them still under the government of a number of petty chiefs.

The earliest time at which we can imagine the consolidation to have taken place consistently with what we know of Assyria is about B.C.760, or nearly half a century later than the date given by Herodotus.
The cause of the sudden growth of Media in power about this period, and of the consolidation which followed rapidly upon that growth, is to be sought, apparently, in fresh migratory movements from the Arian head-quarters, the countries east and south-east of the Caspian.