Cyaxares

With Assyria gone, the Medes claimed the northern and eastern portions of its former territory, stretching their influence from eastern Anatolia to the borders of Central Asia.

Under Cyaxares's son Astyages, the Median realm reached its greatest extent.

It appeared secure, wealthy and unassailable.

Yet in the southern province of Parsa a young Persian prince named Cyrus was watching from inside the Median court.

And first, how all kinds and sorts of men, what degree soever they be, have at all times afore, and now, very honestly use it, the example of most noble men very well doth prove.

Cyaxares, the king of the Medes, and great-grandfather of Cyrus, kept a sort of Scythians with him only for this purpose, to teach his son Astyages to shoot.

Cyrus, being a child, was brought up in shooting, which thing Xenophon would never have made mention on, except it had been fit for all princes to have used.

Seeing that Xenophon wrote Cyrus's life, as Tully saith, not to show what Cyrus did, but what all manner of princes, both in pastimes and earnest matters, ought to do.

In the seventh century before Christ, a Median leader named Deioces began unifying the tribes, establishing a capital at Ecbatana.

His successor, Cyaxares, reorganized the army and participated in the destruction of Nineveh, ending Assyrian dominance, one of the cruelest enemies Israel had ever faced.

The stage was being set.

Then came Cyrus the Great, King of Persia, strategic conqueror, visionary statesman.

The Assyrians, by kind of organizing them, by creating provinces in Median lands, probably provided them with the means to unify.

Which happened then in, at some point in the second half of the seventh century BCE under a king named Cyaxares in the classical sources, Ummanakhtah in the Syrian sources.

And that then, this coalition between the Medes and the Babylonians was just too much for Assyria.

There may be other factors.