Could he have reached Ecbatana, he might have greatly prolonged the struggle; but his enemy pressed him close; and, being compelled to an engagement, he not only suffered a complete defeat, but was made prisoner by his fortunate adversary.
By this capture the Median monarchy was brought abruptly to an end.
Astyages had no son to take his place and continue the struggle.

Even had it been otherwise, the capture of the monarch would probably have involved his people's submission.

In the East the king is so identified with his kingdom that the possession of the royal person is regarded as conveying to the possessor all regal rights.

Cyrus, apparently, had no need even to besiege Ecbatana; the whole Median state, together with its dependencies, at once submitted to him, on learning what had happened.
This ready submission was no doubt partly owing to the general recognition of a close connection between Media and Persia, which made the transfer of empire from the one to the other but slightly galling to the subjected power, and a matter of complete indifference to the dependent countries.

Except in so far as religion was concerned, the change from one Iranic race to the other would make scarcely a perceptible difference to the subjects of either kingdom.