[Illustration: Fig. 347.—Minaret of the Mosque of Kaloum at Cairo.] It was not essential that all the rectangular or square court that forms the mosque should be covered with a roof, provided there was sufficient shelter for the number of worshippers, which was generally small at a time, and if a larger space were required, a portion or all of the open court could be roofed in. What we would call the east end of a church corresponded to that part of a mosque where the _kibla_, or line of direction, would be indicated—towards Mecca—there the _mihrab_ or niche would be fixed. Close to the mihrab is the mimbar, or pulpit, for the sermon, and in close vicinity the _dikka_ or tribune, a raised platform, from which the imām intones the prayers and reads passages from the Korān. The minaret is a later addition, but is seen on every mosque; it is used by the Muezzin, who ascends to its galleries and calls the faithful to prayer five times a day (Fig. 347). A fountain is necessary for the lawful ablutions before prayer. [Illustration: Fig. 348.—Mausoleum at Cairo.] The dome is not a necessary feature to a mosque; it only occurs over the tomb of some sultan or other dignitary, and may be used as a chapel, but only when it covers a tomb. The majority of mosques, however, have a dome, either as a principal feature, or attached to some part of the building. Cairo is particularly rich in domed mausoleum structures (Fig. 348). The domes or cupolas in Moslem buildings generally swell up beyond the semicircle, and are raised considerably by having their lower parts straight-sided or cylindrical; this part is sometimes pierced with a row of small windows, and is recessed back on a pyramid-like story, with a square or polygonal base, which in its turn rests on the top of a square embattled tower. The dome is usually built of brick, the courses projecting roughly one over the other, diminishing towards the top, and thickly plastered over inside and out to get an even surface; sometimes the mortar is thicker than the bricks in Saracen buildings. [Illustration: Fig. 349.—Mosque of Kāit Bey, Cairo. (L.-P.)] Wooden frames are often used in the construction of domes which support the plaster work. Some domes are built with slabs of stones on which a geometric pattern is carved on the outside (Figs. 348, 349); these are generally of a late period, as the tomb mosque of Kāit Bey, built about A.D. 1468 (Fig. 349). The oldest mosque in Cairo is that of Ibn Tūlūn (Fig. 350). It is a cloistered mosque, is built in a massive style, and has a high plain wall around it; it covers about four hundred square feet of ground. In the centre of the inner courtyard is a square stone building surmounted by a dome, one of the earliest carried on stalactites. This building is a century later than the cloisters, and is built over a well or fountain.