“There is no greater mistake than to imagine that the Arabs, who spread with such astonishing rapidity over half the civilized world, were in any real sense a united people. So far was this from being the truth, that it demanded all Mohammed's diplomatic skill, and all his marvellous personal prestige, to keep up a semblance of unity even while he was alive. The Arabs were made up of a number of hostile tribes or clans, many of whom had been engaged in deadly blood-feuds for several generations, and all of whom were moved by a spirit of tribal jealousy which was never entirely extinguished. Had the newly-founded Mohammedan State been restrained within the borders of Arabia, there can be no doubt that it would speedily have collapsed in the rivalry of the several clans;”