709-713. They cross the straits of Gibraltar, and invade and conquer Spain. "At the death of Mohammad, in 632, his temporal and religious sovereignty embraced and was limited by the Arabian Peninsula. The Roman and Persian empires, engaged in tedious and indecisive hostility upon the rivers of Mesopotamia and the Armenian mountains, were viewed by the ambitious fanatics of his creed as their quarry. In the very first year of Mohammad's immediate successor, Abubeker, each of these mighty empires was invaded. The crumbling fabric of Eastern despotism is never secured against rapid and total subversion; a few victories, a few sieges, carried the Arabian arms from the Tigris to the Oxus, and overthrew, with the Sassanian dynasty, the ancient and famous religion they had professed. Seven years of active and unceasing warfare sufficed to subjugate the rich province of Syria, though defended by numerous armies and fortified cities; and the Khalif Omar had scarcely returned thanks for the accomplishment of this conquest, when Amrou, his lieutenant, announced to him the entire reduction of Egypt. After some interval, the Saracens won their way along the coast of Africa, as far as the Pillars of Hercules, and a third province was irretrievably torn from the Greek empire. These western conquests introduced them to fresh enemies, and ushered in more splendid successes. Encouraged by the disunion of the Visigoths, and invited by treachery, Musa, the general of a master who sat beyond the opposite extremity of the Mediterranean Sea, passed over into Spain, and within about two years the name of Mohammad was invoked under the Pyrenees."--[HALLAM.] CHAPTER VII. -- THE BATTLE OF TOURS, A.D. 732, "The events that rescued our ancestors of Britain, and our neighbours of Gaul, from the civil and religious yoke of the Koran."--GIBBON. The broad tract of champaign country which intervenes between the cities of Poictiers and Tours is principally composed of a succession of rich pasture lands, which are traversed and fertilized by the Cher, the Creuse, the Vienne, the Claine, the Indre, and other tributaries of the river Loire. Here and there, the ground swells into picturesque eminences; and occasionally a belt of forest land, a brown heath, or a clustering series of vineyards, breaks the monotony of the wide-spread meadows; but the general character of the land is that of a grassy plain, and it seems naturally adapted for the evolutions of numerous armies, especially of those vast bodies of cavalry which, principally decided the fate of nations during the centuries that followed the downfall of Rome, and preceded the consolidation of the modern European powers.