The Median Empire was in extent and fertility of territory-equal if not superior to the Assyrian. It stretched from Rhages and the Carmanian desert on the east to the river Halys upon the west, a distance of above twenty degrees, or about 1,300 miles. From north to south it was comparatively narrow, being confined between the Black Sea, the Caucasus, and the Caspian, on the one side, and the Euphrates and Persian Gulf on the other. Its greatest width, which was towards the east, was about nine, and its least, which was towards the west, was about four degrees. Its area was probably not much short of 500,000 square miles. Thus it was as large as Great Britain, France, Spain, and Portugal put together. In fertility its various parts were very unequal. Portions of both Medias, of Persia, of Armenia, Iberia, and Cappadocia, were rich and productive; but in all these countries there was a large quantity of barren mountain, and in Media Magna and Persia there were tracts of desert. If we estimate the resources of Media from the data furnished by Herodotus in his account of the Persian revenue, and compare them with those of the Assyrian Empire, as indicated by the same document, we shall find reason to conclude, that except during the few years when Egypt was a province of Assyria, the resources of the Third exceeded those of the Second Monarchy. The weakness of the Empire arose chiefly from its want of organization. Nicolas of Damascus, indeed, in the long passage from which our account of the struggle between Cyrus and Astyages has been taken, represents the Median Empire as divided, like the Persian, into a number of satrapies but there is no real ground for believing that any such organization was practised in Median times, or to doubt that Darius Hystaspis was the originator of the satrapial system. The Median Empire, like the Assyrian, was a congeries of kingdoms, each ruled by its own native prince, as is evident from the case of Persia, where Cambyses was not satrap, but monarch. Such organization as was attempted appears to have been clumsy in the extreme. The Medes (we are told) only claimed direct suzerainty over the nations immediately upon their borders; remoter tribes they placed under these, and looked to them to collect and remit the tribute of the outlying countries. It is doubtful if they called on the subject nations for any contingents of troops. We never hear of their doing so. Probably, like the Assyrians, they made their conquests with armies composed entirely of native soldiers, or of those combined with such forces as were sent to their aid by princes in alliance with them.