When the Arabs first issued from the desert, they must have been surprised at the ease and rapidity of their own success. But when they advanced in the career of victory to the banks of the Indus and the summit of the Pyrenees; when they had repeatedly tried the edge of their cimeters and the energy of their faith, they might be equally astonished that any nation could resist their invincible arms; that any boundary should confine the dominion of the successor of the prophet. The confidence of soldiers and fanatics may indeed be excused, since the calm historian of the present hour, who strives to follow the rapid course of the Saracens, must study to explain by what means the church and state were saved from this impending, and, as it should seem, from this inevitable, danger. The deserts of Scythia and Sarmatia might be guarded by their extent, their climate, their poverty, and the courage of the northern shepherds; China was remote and inaccessible; but the greatest part of the temperate zone was subject to the Mahometan conquerors, the Greeks were exhausted by the calamities of war and the loss of their fairest provinces, and the Barbarians of Europe might justly tremble at the precipitate fall of the Gothic monarchy. In this inquiry I shall unfold the events that rescued our ancestors of Britain, and our neighbors of Gaul, from the civil and religious yoke of the Koran; that protected the majesty of Rome, and delayed the servitude of Constantinople; that invigorated the defence of the Christians, and scattered among their enemies the seeds of division and decay.