The Period of Invasions 193 Jerusalem, Damascus, and Cairo. They have great courts sur- rounded by covered colonnades and are adorned with beautiful marbles and mosaics and delightful windows with bright stained glass. The walls are decorated with passages from the Koran, and the floors are covered with rich rugs. They have one or more minarets, from which the call to prayer is heard five times a day. 305. Rise of the Oriental Empire of the Moslems. The Moslem leaders who succeeded to Mohammed's power were called caliphs. As rulers they proved to be men of the greatest ability. They organized the untamed desert nomads, who now added a burning religious zeal to the wild courage of barbarian Arabs. This combination made the Arab armies of the caliphs irresistible. Within a few years after Mohammed's death they took Egypt and Syria from the feeble successors of Justinian at Constan- tinople. They thus reduced the Eastern Empire to little more than the Balkan Peninsula and Asia Minor. At the same time the Arabs crushed the empire of the New Persians ( 276), but took over their city civilization. With the ruins of Babylon looking down upon them the Mos- lems built their splendid capital at Bagdad beside the New Per- sian royal residence at Ctesiphon. Here, as Sargon's people and as the Persians had so long before done, the Arabs learned to read and write and could thus put the Koran into writing. Here, too, they learned the business of government and became experienced rulers. Thus beside the shapeless mounds of the older capitals Akkad, Babylon, and Ctesiphon the power and civilization of the Orient rose into new life for the last time. Bagdad became the finest city of the East and one of the most splendid in the world. The caliphs extended their power eastward to the frontiers of India. 306. The Moslem Advance to the West; the Battle of Tours. Westward the Moslems pushed along the African coast of the Mediterranean, as their Phoenician kindred had done before them (83). Only two generations after the death of Moham- med the Arabs crossed over from Africa into Spain (A.D. 711) ; then they moved on into France and threatened to girdle the entire
