The tribe of Kinana, to which the _qalammas_ belonged, inhabited the district around Mecca, and the famous tribe of the Koraish, its most distinguished branch, was supreme in Mecca[916]. The calendar regulation therefore took place in the interests of Mecca and its trade, and it is quite ridiculous to say that the sanctity of a month was transferred to another merely in order to render possible a predatory excursion. Besides this would make matters no better, since all the tribes concerned would have to have peace or war in the same months. A shifting of this nature would only be really effectual if it offered a means of surprising an unsuspecting neighbour in time of peace. Probability therefore also points to the view that the _nasî_ was a genuine intercalation carried out by a person appointed for the purpose, so that the dates of the markets and the pilgrimage might be fixed at the proper times of the year. For this no intercalary cycle was employed, any more than elsewhere: the empirical intercalation sufficed, and it was made known to the people at the feast of pilgrims, whence the knowledge spread all over. However the entrusting of such power over the calendar to one individual lends itself only too easily to abuses with a view to ends which have nothing to do with the calendar. The stock example is afforded by the Roman pontifices at the end of the Republic. It is therefore nothing to wonder at that the calendar should have been disorganised during Mohammed’s stay in Mecca. Hence also the attempts at determining the calendar from two or three certainly known dates are vain, for when a system is lacking or is broken up it is impossible to compute a calendar systematically from a couple of dates. Mohammed’s action is thus to be explained:--The misuse of the intercalation had destroyed the dependence of the pilgrimage upon the time of the year: Mohammed wished to create order, and did so in radical fashion by forbidding the intercalation, the misuse of which he saw, but the usefulness of which he failed to recognise.