The sweeping conquests of the decade 632-642 A.D. were followed in later years by a further extension of the boundaries of the Arabian Empire. In the remote East the Arabs sent their victorious armies beyond the Oxus and Indus rivers to central Asia and India. They captured the island of Cyprus, annexed parts of Armenia and Asia Minor, and at length threatened to take Constantinople. Had that city fallen, all eastern Europe would have been laid open to invasion. [Illustration: Map, EXPANSION OF ISLAM] SIEGE OF CONSTANTINOPLE, 716-717 A.D. The first attempts on Constantinople were made by sea and were repulsed, but during the years 716-717 A.D. the city had to face a combined attack by a Moslem navy and army. The eastern emperor, Leo the Isaurian, conducted a heroic defense, using with much effectiveness the celebrated mixture known as "Greek fire." This combustible, probably composed of sulphur, naphtha, and quicklime, was poured or hurled on the enemy's ships in order to burn them. "Greek fire," the rigors of an uncommonly severe winter, and timely aid from the Bulgarians at length compelled the Arabs to beat a retreat. Their failure to take Constantinople gave the Roman Empire in the East another long lease of life. [Illustration: NAVAL BATTLE SHOWING USE OF "GREEK FIRE" From a Byzantine manuscript of the fourteenth century at Madrid. "Greek fire" in marine warfare was most commonly propelled through long tubes of copper which were placed on the prow of a ship and managed by a gunner. Combustibles might also be kept in tubes flung by hand and exploded on board the enemy's vessel.] 134. EXPANSION OF ISLAM IN NORTH AFRICA AND SPAIN NORTH AFRICA SUBDUED Though repulsed before the impregnable walls of Constantinople, the Arabs continued to win new dominions in other North Africa parts of the Christian world. After their occupation of Egypt, they began to overrun North Africa, which Justinian, little more than a century earlier, had reconquered from the Vandals. [10] The Romanized provincials, groaning under the burdensome taxes imposed on them by the eastern emperors, made only a slight resistance to the Moslem armies. A few of the great cities held out for a time, but after the capture and destruction of Carthage [11] in 698 A.D., Arab rule was soon established over the whole extent of the Mediterranean coast from Egypt to the Atlantic. ARABS AND BERBERS Islam made in North Africa one of its most permanent conquests. After the coming of the Arabs many of the Christian inhabitants appear to have withdrawn to Spain and Sicily, leaving the field clear for the introduction of Arabian civilization. The Arabs who settled in North Africa gave their religion and government to the Berbers, as the natives of the country were called, and to some extent intermingled with them. Arabs and Berbers still comprise the population of North Africa, though their once independent states have now been absorbed by European powers. [12]