In our sceptical times there is very little that is above criticism, and one day or other we may expect to hear that Mohammed never existed. The arguments for this can hardly be weaker than those of Casanova against the authenticity of the Qorân. Here we may acknowledge the great power of what has been believed in all times, in all places, by all the members of the community ("quod semper, quod ubique, quod ab omnibus creditum est"). For, after the death of Mohammed there immediately arose a division which none of the leading personalities were able to escape, and the opponents spared each other no possible kind of insult, scorn, or calumny. The enemies of the first leaders of the community could have wished for no more powerful weapon for their attack than a well-founded accusation of falsifying the word of God. Yet this accusation was never brought against the first collectors of the scattered revelations; the only reproach that was made against them in connexion with this labour being that verses in which the Holy Family (Ali and Fatimah) were mentioned with honour, and which, therefore, would have served to support the claims of the Alids to the succession of Mohammed, were suppressed by them. This was maintained by the Shi'ites, who are unsurpassed in Islâm as falsifiers of history; and the passages which, according to them, are omitted from the official Qorân would involve precisely on account of their reference to the succession, the mortality of Mohammed. All sects and parties have the same text of the Qorân. This may have its errors and defects, but intentional alterations or mutilations of real importance are not to blame for this. Now this rich authentic source--this collection of wild, poetic representations of the Day of judgment; of striving against idolatry; of stories from Sacred History; of exhortation to the practice of the cardinal virtues of the Old and New Testament; of precepts to reform the individual, domestic, and tribal life in the spirit of these virtues; of incantations and forms of prayer and a hundred things besides--is not always comprehensible to us. Even for the parts which we do understand, we are not able to make out the chronological arrangement which is necessary to gain an insight into Mohammed's personality and work. This is not only due to the form of the oracles, which purposely differs from the usual tone of mortals by its unctuousness and rhymed prose, but even more to the circumstance that all that the hearers could know, is assumed to be known. So the Qorân is full of references that are enigmatical to us. We therefore need additional explanation, and this can only be derived from tradition concerning the circumstances under which each revelation was delivered.