561, three years before the Persian revolt broke out.

His son, Evil-Merodach, who would probably have maintained his father's alliances, had survived him but two years: he had been murdered in B.C.559 by a brother-in-law, Nergalsharezer or Neriglissar, who ascended the throne in that year and reigned till B.C.555.

This prince was consequently on the throne at the time of Astyages' need.

As he had supplanted the house of Nebuchadnezzar, he would naturally be on bad terms with that monarch's Median connections; and we may suppose that he saw with pleasure the fall of a power to which pretenders from the Nebuchadnezzar family would have looked for support and countenance.
In conclusion, a few words may be said on the general character of the Median Empire, and the causes of its early extinction.
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.