But in the following spring he made the discovery which still remains the most striking achievement of the expedition, and has rehabilitated the fame of that ancient city. This was the great Ishtar Gate, which spanned Babylon's Sacred Way, and the bulls and dragons with which it was adorned have proved that the glyptic art of Babylonia attained a high level of perfection during its later period. The gate was erected at the point where the Sacred Way entered the older city. It was, in fact, the main gate in the two walls of crude brick along the north side of the Citadel, which we have seen reason to believe were the famous defences, Imgur-Bêl and Nimitti-Bêl.[95] Its structure, when rebuilt by Nebuchadnezzar, was rather elaborate.[96] It is a double gateway consisting of two separate gate-houses,[97] each with an outer and an inner door.[98] The reason for this is that the line of fortification is a double one, and each of its walls has a gateway of its own. But the gates are united into a single structure by means of short connecting walls, which complete the enclosure of the Gateway Court.[99] [Illustration: FIG. 14. GROUND-PLAN OF THE ISHTAR GATE. The ground-plan of the gateway is indicated in black; other walls and buildings are hatched. A: Sacred Way to north of gate. B: Gate of outer wall. C: Gateway Court. D: Gate of inner wall. E: Space between west wings. F: Space between east wings. G: Sacred Way to south of gate. H: North-east corner of Palace. K: Temple of the goddess Ninmakh. S: Steps leading down from level of Sacred Way. 1, 2: Doorways of outer gate. 3, 4: Doorways of inner gate. (After Koldewey.)] Dr. Koldewey considers it probable that this court was roofed in, to protect the great pair of doors, which swung back into it, from the weather. But if so, the whole roofing of the gateway must have been at the same low level; whereas the thick walls of the inner gate-house suggest that it and its arched doorways rose higher than the outer gateway, as is suggested in the section[100] and in the reconstruction of the Citadel.[101] [Illustration: FIG. 15. SECTION OF THE ISHTAR GATE. The section is conjecturally restored, looking from west to east; the index capitals and figures correspond to those in Fig. 14. A: Sacred Way to north of gate. B: Gate of outer wall. C: Gateway Court. D: Gate of inner wall. G: Sacred way to south of gate. 1, 2: Doorways of outer gate. 3, 4: Doorways of inner gate, _a_: Traces of pavement. 6: Level of second pavement, _c_: Level of final pavement. _d_: Present ground-level, _e_: Level of ground before excavation. It will be noticed that the portions of the gate preserved are all below the final pavement-level. (After Andrae.)]