I must pass from what went before to what came after and draw a comparison between the palace of Khusrau and the desert palace of Ukhaiḍir. A characteristic feature of the latter, the girdle of walls, must be left out of account. At Qaṣr-i-Shîrîn the walls were placed round the large pleasure-grounds with which the Sasanian king surrounded his dwelling. It is the wall-less Ukhaiḍir, the Ukhaiḍir as it was originally conceived by its builders, which must be taken into consideration, though even in that first design the desert ḥîrah was not left entirely defenceless, since it was compressed into the rectangle of its own enclosing walls, strengthened by towers. The space within those walls had to be utilized to the full. At Qaṣr-i-Shîrîn the guards could be lodged in the lower rooms about the stairways, at Ukhaiḍir they were gathered together within the main entrance. The great hall is, in fact, a monumental gateway. It belongs to the system of defences which is absent from the Sasanian palaces. The Mohammadan builders reverted to an older type, to the fortified palace of the ancient East. At Khorsâbâd the principal entrance to the palace lay within the walls of the acropolis, and it was not, therefore, strongly fortified, but such gates as those in the acropolis walls are the true progenitors of the Ukhaiḍir scheme (Plate 78, Fig. 1). In Sargon’s palace the long entrance passage, some 10 metres wide, represents the great hall of Ukhaiḍir; the lateral chambers on either side are divided at Ukhaiḍir into groups of smaller lateral rooms which, both at Khorsâbâd and at Ukhaiḍir, were very insufficiently lighted. In either case some additional light is obtained from a court into which the chambers open. The symmetrical arrangement of the Ukhaiḍir gate with the central court and audience rooms behind it would not have appealed to ancient authorities on fortification. Chaldaean and Assyrian gateways are seldom if ever situated opposite to one another, an asymmetrical disposition being accounted better for purposes of defence.[150] The long passage room of Khorsâbâd and Ukhaiḍir, but without the lateral chambers, exists in some of the excavated gateways at Susa,[151] and at Susa above the gateway stands a hypostyle pavilion offering a high and airy abode to the great folk who inhabited the palaces within, just as at Ukhaiḍir an open court with lîwâns on all sides occupies the high summit of the gate-house. At Ukhaiḍir there is no direct communication between the ground floor of the gate-house block and the rest of the palace, except one door out of the great hall. The gate tower and hall, with the adjoining rooms for dependants, and the mosque, which had of necessity to be accessible to all, formed the public part of the building, and the upper stories, since they too could only be reached by passing through the public rooms, cannot be regarded as containing private apartments. The better rooms may have been intended for guests; the chambers in the