On this point there has been from the earliest days of Arabic literature a dispute which has been still further complicated by modern hypotheses[911]. According to one view _nasî_ is the intercalation of a month, which served to bring the months into agreement with the solar year[912]. Some authors have even attempted to establish an intercalary cycle, and it has been asserted that the intercalation was borrowed from the Jews. This opinion may be left out of account, since the cycles differ among themselves and are therefore invented, while the intercalation was governed by a hereditary _nasî_-controller from the tribe of Kinâna, who was called the _qalammas_, i. e. ‘Sea of Wisdom’. If the intercalation is controlled by a central authority, as e. g. in Babylonia, an intercalary cycle is unnecessary: the central authority supplies its place. According to the other view the _nasî_ consists in the transferring of the holy character of one month to another, e. g. the declaring of _muharram_ as free and the pronouncing of _safar_ as holy instead of it. This view is based on the supposition that the Arabs found a time of peace lasting for three successive months burdensome, and in order to be able to make predatory excursions in a holy month, and yet keep the number of holy months unchanged, they made another month holy instead. The treatment e. g. of the _karneios_ by the Argives and of the _daisios_ by Alexander the Great[913] was very similar. Therefore, it is maintained, before Mohammed the year was a purely lunar one, and Mohammed only forbade the disarrangement of the holy period. These authorities also ascribe the right of changing the holy month to the _qalammas_, who at the end of the feast of pilgrims in _dhu-l-hijja_ rose and in an address to the assembly arranged the re-distribution. A third view, according to which the feast of pilgrims was held eleven days later every year, until after a cycle of 33 years it came back again to the same month, is certainly incorrect, since the feast was connected with the phases of the moon. The theory is extracted from the comparison between the lunar and the solar years[914].