But greater yet was the difference which separated this empire from all that had preceded it. Omar ruled with absolute power as chalif of Mohammed, whose right to power of any kind, civil or religious, lay only in his office of prophet. The Roman emperor ruled because he was lord of a subject-confederacy of nations, which the Roman arm and the Roman mind had, bit by bit, subdued and wrought together, and which, when so constituted, had been deposited entire by secular warranty in his single hand. But Mohammed ruled, and after him the chalifs, because he was “the Apostle of God,” by a divine commission, whole and entire, from which civil and religious authority equally emanated, but in which the religious was the root of the civil. Such was the power which the companions of Mohammed in the first election of Abu Bekr, launched upon the world, and which, as second chalif, Omar received. And in the spirit of this, he ruled the huge empire of conquest, which stretched from the African Tripolis to the end of Persia, and from the southernmost point of Egypt to the Cilician Taurus, engulphing Alexandria, Antioch, and Jerusalem. No portion of this power did Omar wield without assuming to represent the person who made himself, or was made by others, his followers, the last and highest of the prophets; who was willing indeed to acknowledge Jesus, the Son of Mary, in the number of prophets, but only on the condition that the prophetical list was closed in himself, that it pointed to himself, and was crowned in himself. The Mohammedan war-cry, to die for which was to be a martyr, “There is no God but God, and Mohammed is his prophet,” was at once the denial of the Christian Trinity, and of Christ’s Redeemership. All those who bore it, fought for it, died for it, proclaimed an absolute hostility to the Christian faith, and a definite substitution of another faith for it, and another person on whom that faith rested. This was the empire personified in Omar; and this, in the ten years from 634 to 644, seized upon the southern half of what had been the inheritance bequeathed by Constantine to his successors. The new realm was ruled by Omar with singleness of purpose and unbending resolution to make the Mohammedan standard victorious over the cross, to dethrone Christ for Mohammed.