THE CONQUEST OF EGYPT (638).--The reduction of Persia was not yet fully accomplished, when the Caliph Omar, the successor of Abubekr, commissioned Amrou, the chief whose valor had won many of the cities of Palestine, to carry the standard of the Prophet into the Valley of the Nile. Alexandria, after holding out against the arms of the Saracens for more than a year, was at length abandoned to the enemy. Amrou, in communicating the intelligence of the important event to Omar, wrote him also about the great Alexandrian Library, and asked him what he should do with the books. Omar is said to have replied: "If these books agree with the Koran, they are useless; if they disagree, they are pernicious: in either case they ought to be destroyed." Accordingly the books were distributed among the four thousand baths of the capital, and served to feed their fires for six months. THE CONQUEST OF NORTHERN AFRICA (643-689).--The lieutenants of the Caliphs were obliged to do much and fierce fighting before they obtained possession of the oft-disputed shores of North Africa. They had to contend not only with the Græco-Roman Christians of the coast, but to battle also with the idolatrous Moors of the interior. Furthermore, all Europe had begun to feel alarm at the threatening advance of the Saracens; so now Roman soldiers from Constantinople, and Gothic warriors from Italy and Spain hastened across the Mediterranean to aid in the protection of Carthage, and to help arrest the alarming progress of these wild fanatics of the desert. But all was of no avail. Destiny had allotted to the followers of the Apostle the land of Hannibal and Augustine. Carthage was taken and razed to the ground, and the entire coast from the Nile to the Atlantic, was forced to acknowledge the authority of the Caliphs. By this conquest all the countries of Northern Africa, whose history for a thousand years had been intertwined with that of the opposite shores of Europe, and which at one time seemed destined to share in the career of freedom and progress opening to the peoples of that continent, were drawn back into the fatalism, the despotism, and the stagnation of the East. From being an extension of Europe, they became once more an extension of Asia.