appreciated the pleasure as well as the profit to be gained from splendid architecture; and when, fifty years after the conquest, the fifth Omayyad Khalif, ʾAbd al-Melek ibn Marwan, founded the Dome of the Rock in Jerusalem, he took every advantage of his ample opportunity. He used the traditional skill of the workers established in the country; and he employed the unsurpassed building materials that lay ready. The traditions of the workers were, of course, Byzantine; and the famous domed shrine that they erected was consequently Byzantine in character. This character the shrine has, to a large extent, retained even to the present day, notwithstanding the many changes in method or style of architectural expression that have developed during the long life of the Dome of the Rock, and have, from time to time, been incorporated with the structure or with its decoration. The columns used by ʾAbd al-Melek were taken from earlier buildings or, rather, from their ruins; some, possibly, from the ruins of Constantine's basilica of the Holy Sepulchre, which the Persians had destroyed. Internally the enclosing octagon wall was covered, as it still is, with marble slabs in the Byzantine manner. The dome, the drum on which it rests and the supporting arches were decorated with glass mosaics of Byzantine character. Mosaics also covered the outside of the building, except the lower half of the octagon wall, which then, as now, was clothed in marble. Within the shrine the mosaic method of decoration has survived in the main, with the important exception of the dome. But externally a decoration of glazed tiles has taken the place of the mosaics. Thus, though inside there is much left of the original Byzantine character, yet, outside, the Dome of the Rock is now clothed in a Persian dress, the product of an art of high antiquity that can be traced back to four hundred years before our era and to the coloured glazes of Susa. Earthquakes, fire, winter storms, hands of varying degrees of skill directed by minds as varied in their taste as in their intentions, together with periods of neglect due to political conditions, have all played their part in the production of the Dome of the Rock as we know it to-day.