24 A Short History of the Middle East the pagan aristocracy of Arabia who, fully exposed in their new Syrian environment to the influences of the old blend of Greek and Oriental civilization, were ready to assimilate it and adapt it to both their secular and religious purposes. The almost total de- ficiency of Arab culture in the sciences and liberal and useful arts, and the supremacy in these matters of the Christians, Jews, and Persians, were freely acknowledged. The conquered peoples were regularly employed in commerce and industry, banking, the arts, as architects, engineers, and irrigation-specialists, as schoolmasters and secretaries, even as court-physicians and political advisers. The caliphs at Baghdad in the ninth and tenth centuries had some Christian wazirs (viziers), and most of the court-physicians in the early centuries of Muslim rule were Nestorians. The employment of Christian advisers in Egypt as late as the fourteenth century was a cause of annoyance to fanatical Muslims.1 The only function ab- solutely reserved to Muslims was service in the army and navy. Not only were the Umayyad caliphs' country-palaces decorated in a mixture of Graeco-Syrian and Mesopotamian-Persian styles which completely disregarded the orthodox Muslim ban on the human figure,2 but also Graeco-Syrian influences strongly affected the development of the mosque, whose architecture was still rudimentary at the beginning of the Umayyad period. Though the Dome of the Rock at Jerusalem (often miscalled the Mosque of Omar), which was founded in 691 by Abd ul-Malik, was a shrine built for Muslim worship, it must nevertheless be re- garded as a product of Christian art. Its plan, a circle within an octagon, existed in the Church of the Ascension then standing on the Mount of Olives, and elsewhere in Palestine and Syria. The geometric setting-out of the plan and elevation of the Dome of the Rock appears to be derived from Syrian-Christian architectural practice. Before its exterior was re-covered with Persian tiles in the sixteenth century it was covered with marble and mosaic, and its external appearance must then have been as Byzantine as its internal appearance still largely is.3 The Great Mosque at Damas- cus, founded in 708, was likewise the work of architects and builders supplied from the Byzantine Empire. 1 A. S. Tritton, The Caliphs and their Non-Muslim Subjects. J. H. Kraemer, Encyclopaedia of Mam, art. Egypt, 7. 2 e.g. the recently-discovered palace at Khirbat Mafjar near Jericho: Quarterly of the Dept, of Antiquities of Palestine, XII (1945), 17 ff. 8 E. T. Richmond, Moslem Architecture (623-1516), chu II.