XX THE WALLS OF THE FORTIFICATIONS AND QUAYS TO THE WEST AND NORTH OF THE SOUTHERN CITADEL. We must now turn to the consideration of the fortifications that are connected both directly and indirectly with the Southern Citadel. It is not always easy to gain a clear idea of these structures. In course of time the walls are displaced, the area enlarged, ancient walls are demolished, and the whole appearance of the place altered. All this occurred to a marked extent during the 43 years of Nebuchadnezzar’s reign. Of the period previous to that we have only the Arachtu wall of Nabopolassar, and the supporting wall of the Assyrian Sargon north-west of the palace of Nabopolassar, which are marked A and S on the plan (Fig. 81). We will first examine those various walls in order to learn their purport and their extent, and then attempt to realise this somewhat complicated system of fortifications in its entire aspect and gradual formation. [Illustration: FIG. 81.—The north-west corner of the Southern Citadel. A1 Arachtu wall of Nabopolassar, 1st period. A2 Arachtu wall, 2nd period. A3 Arachtu wall, 3rd period. ÄG Older moat wall. B Wells. G Graves. GI Moat wall of Imgur-Bel. NL Northern mud wall. NP Palace of Nabopolassar. NS Northern wall of Southern Citadel. PZ Parallel intermediate wall. QW Cross wall with outlets for water. S Sargon wall. SL Southern wall of mud brick. VM Connecting wall. WS Western part of the Southern Citadel. WV Western outworks of the Southern Citadel. ] XXI THE MOAT WALL OF IMGUR-BEL We began our investigation of the western portion of the Southern Citadel, so far as we have carried it at present, by cutting a long and wide trench (Figs. 84, 85), which, in its western part, laid bare the walls of the western outworks, which in places are remarkably thick. [Illustration: FIG. 82.—The moat wall of Imgur-Bel, west of the Southern Citadel. ] [Illustration: FIG. 83.—Inscribed brick from the moat wall of Imgur-Bel. ] [Illustration: FIG. 84.—Trench on the west of the Southern Citadel, during excavation. ] [Illustration: FIG. 85.—Trench on the west of the Southern Citadel, completely excavated. ]