to the Mohammedan lunar months--two years is a rough approximation for ‘sometimes two, sometimes three years’--because it was to be kept in place in regard to the solar year. But the pilgrimage took place in a definite month, and therefore the months also belonged to a lunisolar year. If the months of the lunisolar year are compared with those of the lunar year confusion results, since both series have the same names. Let us take, for example, a sentence of the distinguished chronologist Albiruni, who represents the opinion that _nasî_ means the intercalation of a month: “The first intercalation applied to _muharram_, in consequence _safar_ was called _muharram_, _rabi I_ was called _safar_, and so on; and in this way all the names of all the months were changed. The second intercalation applied to _safar_; in consequence the next following month (_rabi I_, the original _rabi II_)[915] was called _safar_, and this went on till the intercalation had passed through all twelve months and returned to _muharram_.” When other writers, not so well trained in chronology, say that the hallowing of the month was transferred from _muharram_ to _safar_ and from _safar_ to _rabi I_, this means that, according to the year, the _safar_ or _rabi I_ of the lunar year corresponds to the _muharram_ of the lunisolar year. When in the speech of the _qalammas_, _safar I_ and _rajab_ are simultaneously shifted to the month following in each case, this involves the shifting of the whole series of months. A genuine intercalation therefore takes place. The term _nasî_, ‘to push aside’, resembles the world-wide description of the intercalation of the month. _Safar I_ is ‘forgotten’, but upon this it follows that not this month is holy, but the following one, which is now also called _safar I_ but corresponds to _safar II_ of the strictly lunar year. The sanctity or non-sanctity of the months was for the people the all-important point, and the _qalammas_, who was a religious authority, was obliged to refer to it. Hence he declared the month as free and the following month as holy without expressing himself, as we should have wished, in the technical terms of chronology. The people understood him: if the month after _dhu-l-hijja_ was free, it followed that not this month but the next was holy, the month with which the new year began, _safar I_. The intercalation therefore involves a transference of the sanctity of the month following the feast of pilgrims to the next but one after the feast. Hence has arisen the misunderstanding that the _nasî_ consisted _only_ in a transference of the sanctity of the months.