Qṣair ‘Amrah lies somewhat outside the architectural type to which the other three buildings belong. It is a small unfortified pleasure-palace with a reception hall and throne-room on a basilical plan, and a bath. Very closely related to it is the early Mohammadan ruin of Ḥammâm al-Ṣarakh, discovered by the Princeton Expedition.[249] The bath at Djebel Sais is not dissimilar, but in the light of our present knowledge it requires re-examination.[250] Both at Qṣair ‘Amrah and at Ḥammâm al-Ṣarakh there is a small dome over a square chamber. At Ḥammâm al-Ṣarakh this chamber is 2·15 metres square; the dome is set on pendentives and lighted by windows. It is laid up in gores with projecting ribs constructed of long, thin, wedge-shaped bits of shale, entirely undressed and completely covered by plaster. When intact it must have presented an appearance not unlike that of the ribbed dome at Ukhaiḍir, except that the ribs were set wider apart and the pendentive substituted for the primitive bracket. Concerning the structural features of the dome at Qṣair ‘Amrah, the publication of the Viennese Academy, which leaves much to be desired, is not explicit. Dr. Musil, who is always the best guide in matters architectural and archaeological, describes it as being set on pendentives and lighted by windows in the dome.[251] Here and at Ḥammâm al-Ṣarakh two semi-domed niches are placed opposite to one another, one at either end of the domed chamber, and a room (3·30 metres square at Ḥammâm al-Ṣarakh) next to the domed chamber is roofed with a groined vault. We have a similar use of the groined vault in the east annex at Ukhaiḍir. At Ḥammâm al-Ṣarakh some of the doors are covered by straight lintels, others (together with all the windows) by semicircular arches. Some of the wider arches are slightly pointed, but the vaults and transverse arches in the reception-room are semicircular. At Qṣair ‘Amrah straight lintels are the rule for doors and windows, but over the architrave of the wide door leading into the audience chamber there is a shallow relieving arch. The three parallel barrel vaults of the audience chamber are visible upon the exterior, and the absence of the flat roof obviates the need of tubes between the vaults. In both of these bâdiyahs the walls were decorated with frescoes. Qṣair ‘Amrah was built between the years 711 and 750, when the house of Umayyah came to an end, the earlier date being determined by the presence among the frescoes of a representation of Roderick, the last king of the West Goths, who came first into contact with the Arabs at the battle of Xeres in 711.[252]