In attempting to extend their conquests northward the Saracens were met by an army under Charles Martel, king of France, A. D. 732. Between Tours and Poictiers a terrible battle was fought, which lasted seven days. The Franks and Goths lost so many that it was impossible to tell the number of the slain. But these losses were more than counterbalanced by the losses of the Saracens whose great general, Abderahman, was found among the slain. Their previous successes had filled them with pride. They looked with contempt upon their enemies. For example, when the Roman emperor, Nicephorous, had sent a threatening letter to the Caliph Haroun-al-Raschid, the latter replied, "In the name of the most merciful {33} God, Haroun-al-Raschid, commander of the faithful, to Nicephorous, the Roman dog! I have read thy letter, O thou son of an unbelieving mother! Thou shalt not hear my words; thou shalt behold my reply!" A few weeks later it was written in letters of blood on the plains of Phrygia. Although the Saracen empire had reached the zenith of its power, in one sense Mahometanism had not reached its culmination. The day was to come, when under the name of Ottoman Turks, it would expel the descendants of the Caesars from their capital, hold the classic land of Greece in subjection, and under the very walls of Vienna dispute the empire of Europe in the center of that continent; and in Africa extend its dogmas and faith across burning deserts and pestilential forests far south of the equinoctial line. It is a mistaken idea that the progress of the Saracens depended on the sword alone. The causes of their success were many and various. One of these, the paganization of Christianity, has already been noticed. The long and desolating wars of the Romans had thrown the whole oriental and African trade into the hands of the Arabs. Hence a commercial interest and sympathy had grown up between these peoples. Another reason was the mildness of the Saracen government in comparison with that of the Romans. The only taxation was a single annual tribute, amounting to less than one-half the various taxes by the Romans. Another feature was complete religious toleration except to idolators. The only creed required was simply, "There is but one God, and Mahomet is His prophet." Still, another cause of Saracen success was the effective plan adopted for the consolidation of their power. In battle they were simply terrible, and the destruction of human life was in some instances without a parallel; yet the widows and children of their fallen foes were universally treated with kindness. As a consequence, the children became ardent disciples of Mahometanism, and the widows often married their former conquerors. This was all the more frequent as polygamy was an established custom. The children of these unions gloried in their descent from their conquering fathers.