The scene now changes from the presence and awful arsenal of the Almighty to the historical consummation of His vengeance. Nahum foresees the siege of Niniveh. Probably the Medes have already overrun Assyria.[253] The _Old Lion_ has withdrawn to his inner den, and is making his last stand. The suburbs are full of the enemy, and the great walls which made the inner city one vast fortress are invested. Nahum describes the details of the assault. Let us try, before we follow him through them, to form some picture of Assyria and her capital at this time.[254] As we have seen,[255] the Assyrian Empire began about 625 to shrink to the limits of Assyria proper, or Upper Mesopotamia, within the Euphrates on the south-west, the mountain-range of Kurdistan on the north-east, the river Chabor on the north-west and the Lesser Zab on the south-east.[256] This is a territory of nearly a hundred and fifty miles from north to south, and rather more than two hundred and fifty from east to west. To the south of it the Viceroy of Babylon, Nabopolassar, held practically independent sway over Lower Mesopotamia, if he did not command as well a large part of the Upper Euphrates Valley. On the north the Medes were urgent, holding at least the farther ends of the passes through the Kurdish mountains, if they had not already penetrated these to their southern issues. The kernel of the Assyrian territory was the triangle, two of whose sides are represented by the Tigris and the Greater Zab, the third by the foot of the Kurdistan mountains. It is a fertile plain, with some low hills. To-day the level parts of it are covered by a large number of villages and well-cultivated fields. The more frequent mounds of ruin attest in ancient times a still greater population. At the period of which we are treating, the plains must have been covered by an almost continuous series of towns. At either end lay a group of fortresses. The southern was the ancient capital of Assyria, Kalchu, now Nimrud, about six miles to the north of the confluence of the Greater Zab and the Tigris. The northern, close by the present town of Khorsabad, was the great fortress and palace of Sargon, Dur-Sargina:[257] it covered the roads upon Niniveh from the north, and standing upon the upper reaches of the Choser protected Niniveh’s water supply. But besides these there were scattered upon all the main roads and round the frontiers of the territory a number of other forts, towers and posts, the ruins of many of which are still considerable, but others have perished without leaving any visible traces. The roads thus protected drew in upon Niniveh from all directions. The chief of those, along which the Medes and their allies would advance from the east and north, crossed the Greater Zab, or came down through the Kurdistan mountains upon the citadel of Sargon. Two of them were distant enough from the latter to relieve the invaders from the