We turn now to the date of the Book apart from this prologue. It was written after a great overthrow of the Egyptian Thebes[224] and when the overthrow of Niniveh was imminent. Now Thebes had been devastated by Assurbanipal about 664 (we know of no later overthrow), and Niniveh fell finally about 607. Nahum flourished, then, somewhere between 664 and 607.[225] Some critics, feeling in his description of the fall of Thebes the force of a recent impression, have placed his prophesying immediately after that, or about 660.[226] But this is too far away from the fall of Niniveh. In 660 the power of Assyria was unthreatened. Nor is 652, the year of the revolt of Babylon, Egypt and the princes of Palestine, a more likely date.[227] For although in that year Assyrian supremacy ebbed from Egypt never to return, Assurbanipal quickly reduced Elam, Babylon and all Syria. Nahum, on the other hand, represents the very centre of the empire as threatened. The land of Assyria is apparently already invaded (iii. 13, etc.). Niniveh, if not invested, must immediately be so, and that by forces too great for resistance. Her mixed populace already show signs of breaking up. Within, as without, her doom is sealed. All this implies not only the advance of an enormous force upon Niniveh, but the reduction of her people to the last stage of hopelessness. Now, as we have seen,[228] Assyria proper was thrice overrun. The Scythians poured across her about 626, but there is no proof that they threatened Niniveh.[229] A little after Assurbanipal’s death in 625, the Medes under King Phraortes invaded Assyria, but Phraortes was slain and his son Kyaxares called away by an invasion of his own country. Herodotus says that this was after he had defeated the Assyrians in a battle and had begun the siege of Niniveh,[230] but before he had succeeded in reducing the city. After a time he subdued or assimilated the Medes, and then investing Niniveh once more, about 607, in two years he took and destroyed her.