Upon the trebly fortified city the Medes drew in from east and north, far away from Kalchu and able to avoid even Dur-Sargina. The other fortresses on the frontier and the approaches fell into their hands, says Nahum, like _ripe fruit_.[258] He cries to Niniveh to prepare for the siege.[259] Military authorities[260] suppose that the Medes directed their main attack upon the northern corner of the city. Here they would be upon a level with its highest point, and would command the waterworks by which most of the moats were fed. Their flank, too, would be protected by the ravines of the Choser. Nahum describes fighting in the suburbs before the assault of the walls, and it was just here, according to some authorities,[261] that the famous suburbs of Niniveh lay, out upon the canal and the road to Khorsabad. All the open fighting which Nahum foresees would take place in these _outplaces_ and _broad streets_[262]—the mustering of the _red_ ranks,[263] the _prancing horses_[264] and _rattling chariots_[265] and _cavalry at the charge_.[266] Beaten there the Assyrians would retire to the great walls, and the waterworks would fall into the hands of the besiegers. They would not immediately destroy these, but in order to bring their engines and battering-rams against the walls they would have to lay strong dams across the moats; the eastern moat has actually been found filled with rubbish in face of a great breach at the north end of its wall. This breach may have been effected not only by the rams but by directing upon the wall the waters of the canal; or farther south the Choser itself, in its spring floods, may have been confined by the besiegers and swept in upon the sluices which regulate its passage through the eastern wall into the city. To this means tradition has assigned the capture of Niniveh,[267] and Nahum perhaps foresees the possibility of it: _the gates of the rivers are opened, the palace is dissolved_.[268]