A precise echo of this “practice” may be found in Montah? al-edr?k fi taq?sim al-afl?k by Abu Bakr Mo?ammad b. A?mad al-??beti al-?araqi (Ms. Or. 110 of the Biblioteca Medicea Laurenziana in Florence, fol. 93b): “The Saturday, 12th of the month of Rabi? II in the year 5, year 500 in the era of Yazdejerd, the turn of the kabisa returned to the month of Ordibehe?t, and therefore we held kabisa in the month of Farvardin (fa-kabasn? farvardin-m?h), and we added the 5 epagomenal days to its last days, and so its days numbered thirty-five.” The stated operation explicitly relates to the month of Farvardin, which becomes “stuffed” (makbus). So at this time (12 Rabi? II 525/14 March 1131/1 Ordibehe?t 500 Yazdegerdi = vernal equinox) Andarg?h was shifted to the end of Farvardin. The same information is to be found as a prediction of the next calendar adjustment in ?ahmard?n b. Abe’l-?ayr R?zi’s Raw?at al-monajjemin (ms. Or. 4° 848, mutilated, of the Staatsbibliothek in Berlin; cf. Taqiz?da, p. 20, n. 41, and p. 234).
The persistence of this practice is confirmed by observations in the modern calendars of at least two regions of the Iranian world: in the Pamir region (in many centers of Badakhshan such as ?v??n and ?o?n?n and surrounding areas) there are three Nowruz coexisting today: the ‘regular’ Nowr?z of 1 Farvardin, one preceding 17-18 February (end of Bahman), and one following Ordibehe?t (Karam??hyef, pp. 687-88). For Iran, we have the following report on the usages of the area of ?alaq?n (Gil?n province): “Panje days begin from 25th of Farvardin of every year called ‘Panje Pitok’ in Taleghan and its surrounding villages. Like people of other cities, people of Taleghan calculated every month for thirty days which totally became 360 days in every year. By this calculation, there were five days that belonged to none of the months” (Vakilian, p. 202).
Probably around the 20s of the 12th century—when, in a calendrical system which still remained solar and vague, Nowruz was behind by roughly a month with respect to the beginning of Spring—Andarg?h and Nowruz were displaced by a month, thus giving birth to a calendar with Nowruz on the first of Ordibehe?t and Andarg?h immediately before, that is, at the end of Farvardin (putting into practice the ‘intercalary’ method mentioned in Montah? al-edr?k). We can see an indication of another occurrence of a shift of Andarg?h, to a position between Dey and Bahman, in the five-day discrepancy between Bar-sada and Sada festivals (Cristoforetti, p. 56). But we also have various hints at a popular custom (?ab-e esfand) of shifting Andarg?h to a position between Bahman and Isfand (idem, p. 49).
The Parsi Zoroastrians appear to have applied a kind of kabisa similar to the one described in the Zij al-mofrad, paraphrasing which, one could describe it in the following manner: when the Sun reached the First Point of Aries on the first of Ordibehe?t, they called this month Farvardin, and Farvardin became Esfand?rma?. In spite of a prevailing hostility to changes in the calendar in Zoroastrian quarters, rather than think of the only effective insertion of a supplementary month in the entire history of the Iranian calendar (Boyce, p. 20; de Blois, p. 50), it is preferable to conceive of it as something that is amply testified as widespread throughout the Iranian world.
In conclusion, the mechanism defined by Islamic astronomers as kabisa was extremely simple, but gave rise to various confusions. There was no true intercalation, but rather a periodic readjustment. This practice is attested on the popular (provincial) level, but was officially enacted only once, in the Sasanian era, when Andarg?h seems to have moved to a place following ?b?n. (Bali?ski, p. 101, hypothesizes two displacements of Andarg?h: one in the Parthian and the other in the Sasanian age.) The eventual renaming of the months illustrated by Zij al-mofrad possibly creates another parallel calendar, thus casting light on the issue of the ‘double’ Iranian calendar first hypothesized by A. von Gutschmid and later analyzed by ?. Taqiz?da. At the beginning of the 11th century, something similar was done, displacing Andarg?h until after Esfand?rma?, and during the whole Islamic age we can observe similar, although less thoroughly welcomed, practices.
Source 2: wikipedia.org
History of Minarets
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