The constituents of our present Koran belong partly to the Mecca period (before A.D. 622), partly to the period commencing with the emigration to Medina (from the autumn of 622 to 8th June 632). Mohammed’s position in Medina was entirely different from that which he had occupied in his native town. In the former he was from the first the leader of a powerful party, and gradually became the autocratic ruler of Arabia; in the latter he was only the despised preacher of a small congregation. This difference, as was to be expected, appears in the Koran. The Medina pieces, whether entire súras or isolated passages interpolated in Meccan súras, are accordingly pretty broadly distinct, as to their contents, from those issued in Mecca. In the great majority of cases there can be no doubt whatever whether a piece first saw the light in Mecca or in Medina; and, for the most part, the internal evidence is borne out by Moslem tradition. And since the revelations given in Medina frequently take notice of events about which we have pretty accurate information, and whose dates are at least approximately known, we are often in a position to fix their date with, at any rate, considerable certainty; here, again, tradition renders valuable assistance. Even with regard to the Medina passages, however, a great deal remains uncertain, partly because the allusions to historical events and circumstances are generally rather obscure, partly because traditions about the occasion of the revelation of the various pieces are often fluctuating, and often rest on misunderstanding or arbitrary conjecture. But, at all events, it is far easier to arrange in some sort of chronological order the Medina súras than those composed in Mecca. There is, indeed, one tradition which professes to furnish a chronological list of all the súras. But not to mention that it occurs in several divergent forms, and that it takes no account of the fact that our present súras are partly composed of pieces of different dates, it contains so many suspicious or undoubtedly false statements, that it is impossible to attach any great importance to it. Besides, it is _à priori_ unlikely that a contemporary of Mohammed should have drawn up such a list; and if any one had made the attempt, he would have found it almost impossible to obtain reliable information as to the order of the earlier Meccan súras. We have in this list no genuine tradition, but rather the lucubrations of an undoubtedly conscientious Moslem critic, who may have lived about a century after the emigration.