Over the outer arcade of the Dome of the Rock runs the great Cufic inscription, giving the date of the erection of the building in 688 A.D. The name of Abd el Melek, the fourth of the Ommiyah Khalifs, has been taken out at a later period, and that of Mamûn, one of the Abbasîyeh Khalifs, substituted; but the clumsy forger has forgotten the date, and has used a lighter blue in the grounding, thus the antiquity of the text is the more confirmed by the alteration.
This inscription dates the arcade, and thus apparently the inner circle, but not necessarily the outer wall, which may be later. The doors in this outer wall bear Cufic inscriptions dating 831 A.D., at which time Mamûn restored the building; the beams in the roof resting on the wall bear the date 913 A.D. In the ninth century the pointed arch began to be used by the Arabs, and the outer wall cannot be dated later than this; but if it be, as may naturally be supposed, of the same date with its doors, it is part of the work of El Mamûn, and this agrees with the idea that 'Abd el Melek's Dome of the Rock consisted of two concentric arcades only, proportional to those of the Dome of the Chain. The symmetry of the present proportions is destroyed by the great breadth of the larger building in comparison with its height, which is due simply to the addition of the outer wall. Once remove the outer wall, and the pleasing proportions of the Dome of the Chain are reproduced to three times their scale.
The Dome of the Rock belongs to that obscure period of Saracenic art when the Arabs had not as yet created an architectural style of their own, and when they were in the habit of employing Byzantine architects to build their mosques. Among the rare specimens of their work at this time, is the Mosque of 'Amrû, at Cairo, commenced in 642 A.D., and apparently almost rebuilt by that very 'Abd el Melek whose work in Jerusalem we are now considering.
Of the Egyptian building Mr. Fergusson writes: "It probably now remains in all essential parts as left by these two Caliphsâ ('Abd el Melek and his successor, Walid). It is therefore very interesting to compare the Jerusalem Haram with the Cairo mosque, and the resemblance is striking.