The power of Assyria at this time so vastly preponderated over that of her ancient rival that a single campaign sufficed on each occasion of revolt to crush the nascent insurrection.
A tabular view of the chronology of this period is appended.
[Illustration: PAGE 237] Having thus briefly sketched the history of the kingdom of Babylon from its conquest by Tiglathi-Nin to the close of the long period of Assyrian predominance in Western Asia, we may proceed to the consideration of the "Empire." And first, as to the circumstances of its foundation.
When the Medes first assumed an aggressive attitude towards Assyria, and threatened the capital with a siege, Babylonia apparently remained unshaken in her allegiance.

When the Scythian hordes spread themselves over Upper Mesopotamia and wasted with fire and sword the fairest regions under Assyrian rule, there was still no defection in this quarter.

It was not till the Scythic ravages were over, and the Medes for the second time poured across Zagros into Adiabene, resuming the enterprise from which they had desisted at the time of the Scythic invasion, that the fidelity of the Southern people wavered.
Simultaneously with the advance of the Medes against the Assyrian capital from the east, we hear of a force threatening it from the south, a force which can only have consisted of Susianians, of Babylonians, or of both combined.

It is probable that the emissaries of Cyaxares had been busy in this region for some time before his second attack took place, and that by a concerted plan while the Medes debouched from the Zagros passes, the south rose in revolt and sent its hasty levies along the valley of the Tigris.
In this strait the Assyrian king deemed it necessary to divide his forces and to send a portion against the enemy which was advancing from the south, while with the remainder he himself awaited the coming of the Medes.

The troops detached for the former service he placed under the command of a certain Nabopolassar?
(Nabu-pal-uzur), who was probably an Assyrian nobleman of high rank and known capacity.