But one more struggle remained--it was the death agony of the Persian Empire. The fugitive king gathered to his standard at Nehavend, on the plains of Hamadan, one hundred and fifty thousand men. Tidings were sent to the Caliph Omar at Medina--and there in the Mosque, by a handful of grey-headed Arabs, who but a few years previously had been homeless wanderers, was debated and decided the fate of the once magnificent empires of the Orient,--Syria, Chaldea, Babylonia and the dominions of the Medes and Persians. The army of the Saracens, reinforced by men hardened in war, daring, confident, and led by able generals, was greatly inferior in numbers, but fired with zeal and the courage of death. At the signal given "Allah Achbar" thrice repeated with the shaking of the standard, the army rushed to battle rending the air with the universal shout "Allah Achbar! Allah Achbar!" The shock of the two armies was terrific. In an hour the Persians were routed; by midnight their slain numbered a hundred thousand men, and their Empire was destroyed. The battle of Nehavend commemorated as "The Victory of Victories," took place in the twenty-first year of the Hegira the year six hundred and forty-one of our era, and only nine years after the death of Mohammed. If all Syria fell in six years; if the fate of Persia was decided by a single battle, Egypt may be said to have fallen in a single moment. With the fall of Alexandria perished the largest library of the world, the thesaurus of all the intellectual treasures of antiquity. While Egypt was won almost without a blow, Latin Africa withstood the Saracens for sixty years. But at last it was conquered. Spain also fell. The world staggered. Thirty-six thousand cities, towns and castles had fallen. The armies of the Saracens were victorious from Scinde in India, westward to Constantinople, then southward they had swept through Palestine, Egypt, Northern Africa beyond the Pillars of Hercules into Spain, and were only and finally arrested in Western Europe as all the world knows by Charles Martel in 732 upon the field of Tours. But all the world does not know so well how that in 673 the Saracens were beaten back from the walls of Constantinople and the Commander of the Faithful compelled to purchase peace by an annual tribute of three thousand pieces of gold, fifty slaves and fifty of the finest Arabian horses. The year 717 saw Constantinople again besieged by a Saracen army, but Leo, the Isaurian, again beat back the invader with utter defeat; and no Moslem army ever again appeared under the walls of the New Rome, until a fiercer, ruder, more cruel race of Conquerors from the far East grasped again with bloody hand the sword of the Prophet. CHAPTER III. THE STORY OF THE FIRST CRUSADE.