In pre-Islamic times, pilgrimages were made to sanctuaries in various regions of Arabia. Feasts connected with idolatry and annual fairs were held at convenient seasons of the year. To keep all these events in order, a lunisolar calendar was used, and the calendar adjuster of the Banū Kināna was charged with intercalation (nasīʾ). They inserted a leap month according to the same cycle as the Jewish calendar. Though it was exceptional, in emergency situations (e.g. the war of Fiǧār), they would postpone a sacred month, set to guarantee the safety of pilgrims. In the first decade of hiǧra calendar, in fact, three leap months were inserted immediately after ḏū l-ḥiǧǧa of 1/623, 3/625, and 6/628. On the occasion of the pilgrimage lead by Abū Bakr in 9/631, the leap month was not inserted, and in the following year at the Farewell Pilgrimage, Muḥammad formally abolished intercalation. The day that Muḥammad arrived in Medina was, if the account reported by Ibn Isḥāq is correct, 28th June 622, and the battle of Badr was 2 months earlier than in the standard correspondence.
N. Nebes“A new ʾAbraha inscription from the Great Dam of Mārib”Proceedings of the Seminar for Arabian Studies34 (2004) p. 228. On the Ḥimyarite calendar see also I. Gajda Le royaume de Ḥimyar à l’époque monothéiste: L’histoire de l’Arabie du Sud ancienne de la fin du IVe siècle de l’ère chrétienne jusqu’à l’avènement de l’islam Paris Académie des Inscriptions et Belles-Lettres [Mémoires de l’Académie des Inscriptions et Belles-Lettres 40] 2009 p. 255-273.
According to al-AzraqīAḫbār p. 129 131ʿUkāẓ (administrated by the Banū Qays b. ʿAylān and Banū Ṯaqīf) was held for the first 20 days of the 11th month of ḏū l-qaʿda Maǧanna (by the Banū Kināna) was for the last 10 days of ḏū l-qaʿda and Ḏū l-Maǧāz (by the Banū Huḏayl) was for the first eight days of the 12th month of ḏū l-ḥiǧǧa. Al-Marzūqī Azmina II p. 167-168 reports that ʿUkāẓ was administrated by the Banū Tamīm.
Ibn HišāmSīra p. 30; Ibn Ḥabīb Muḥabbar p. 156-57; al-Masʿūdī Murūǧ III p. 116-117; Ibn al-Kalbī Ǧamharat al-Nasab ed. Nāǧī Ḥasan Beirut ʿĀlam al-kutub 1986 p. 164-165. Al-Azraqī Aḫbār p. 125 however mentions that the Banū Kinda originally had served as calendar adjusters and then Mālik b. Kināna who married a Kindite princess succeeded in that function. The Banū Kinda in the Yemen and Ḥaḍramawt reportedly embraced Judaism in pre-Islamic times and their calendar hence should have been a lunisolar calendar as that of Ḥimyar (see I. Shahīd “Kinda” EI2 ).
Ibn HišāmSīra p. 893-894; al-Ṭabarī Taʾrīḫ I p. 1693. See also al-Wāqidī Maġāzī III p. 990. In this expedition Muḥammad sent Ḫālid b. al-Walīd to Dūmat al-Ǧandal where Ukaydir the king of Dūmat was captured “in a summer moonlit night” (al-Ṭabarī Taʾrīḫ I p. 1702; al-Wāqidī Maġāzī III p. 1025-1026). Although Ibn Hišām reports that the expedition to Tabūk took place in raǧab 9/Oct-Nov 630 this is implausible and too late as a historical date. J. Wellhausen Muhammed in Medina: Das ist Vakidi’s Kitab alMaghazi in verkürzter deutscher Wiedergabe Berlin G. Reimer 1882 p. 19-20 suggests that the expedition took place in rabīʿ II (Jul-Aug).
Ibn ḤabībMunammaq p. 198; Ibn Saʿd Ṭabaqāt I/1 p. 81. Cf. also E.L. Tasseron “The Sinful Wars: Religious Social and Historical Aspects of ḥurūb al-fijār” Jerusalem Studies in Arabic and Islam 8 (1986) p. 44.
M. Effendi“Mémoire sur le calendrier arabe avant l’islamisme, et sur la naissance et l’âge du prophète Mohammad”Journal Asiatique5/11 (1858) p. 109-192. Sh.B. Burnaby makes summary of this article in Elements of the Jewish and Muhammadan Calendars London G. Bell & Sons 1901 p. 460-470.
WellhausenReste p. 95ff describes this point in full detail. See also Wensinck “Ḥadjdj” EI and EI2; H. Lazarus-Yafeh “The Religious Dialectics of the Ḥadjdj” in id. Some Religious Aspects of Islam Leiden Brill 1981 p. 21; S.D. Goitein “Ramadan: the Muslim Month of Fasting its Early Development and Religious Meaning” in id. Studies in Islamic History and Institutions Leiden Brill 1968 p. 92-93.
A.P. Caussin de Perceval“Mémoire sur le calendrier arabe avant l’islamisme”Journal Asiatique4/1 (1843) p. 342-379; “Notes on the Arab Calendar before Islam” transl. L. Nobiron Islamic Culture 21 (1947) p. 135-153. His theory is discussed in detail in Burnaby Elements p. 371-376 and 447-459.
H. Amīr ʿAlī“Fresh Observations on Perceval’s 100 Year Old Notes on the Arab Calendar before Islam”Islamic Culture22 (1948) p. 174-180; “The First Decade in Islam” The Muslim World 44/2 (1954) p. 126-138.
M. Hamidullah“The Nasiʾ, the Hijrah Calendar and the Need of Prepairing a New Concordance for the Hijrah and Gregorian Eras”Journal of the Pakistan Historical Society16/1 (1968) p. 1-18; “The Concordance of the Hijrah and Christian Ears for the Life-Time of the Prophet” Journal of the Pakistan Historical Society 16/4 (1968) p. 213-219. Cf. also F.R. Shaikh “The Veracity of the Arab Pagan Calendar” Islamic Culture 71/1 (1997) p. 41-69.
Cf. Hamidullah “The Concordance” p. 219. A certain degree of care is needed when dealing with the hiǧra calendar. One thing that should be pointed out is that it is impossible to compare the calendar in that period with the Christian calendar with complete precision. The Arabs in those days marked the start of a month by sighting the new moon and there were two 29 day months or 30 day months in a row occasionally. Astronomy nowadays is advanced enough to roughly estimate on what date the new moon could have been sighted. Nevertheless it is impossible to accurately estimate the exact date on which the new moon was sighted because the observation of the new moon depends on the longitude of that area the weather geographic conditions and so on. It is thus impossible to replicate the hiǧra calendar accurately and we have to allow for a 1-2 day drift when comparing it with the Christian calendar. However if historical materials have days of the week as well as dates it may be possible to estimate on what date major incidents happened after the hiǧra since the same days of the week were used among the Jewish/Christian/Islamic calendars.
Amīr ʿAlī“First Decade” p. 129-132. It is strange that he significantly revised his theory in Upstream Downstream: Reconstruction of Islamic Chronology (Khuda Bakhsh Annual Lectures Series 7) Hyderabad 1977.
Caussin de Perceval“Mémoire” p. 378(transl. p. 152) states that it coincides with the first days in July. It is reported in the several traditions that when Muḥammad arrived in Medina he saw the Jewish fasting of ʿāšūrāʾ (Yom Kippur; the Day of Atonement) and ordered the fasting for Muslims as well (cf. Goitein “Ramadan” p. 95-96). The day of Yom Kippur (10 Tishri) in ad 622 is calculated in 20 September in the correspondence of Burnaby (table 6). Among the modern scholars then there might be views which prefer mid-September as the date of the hiǧra (Muḥammad’s arrival in Medina) to the end of June but as Wagtendonk (Fasting p. 126) maintains Muḥammad’s arrival does not have to coincide exactly with Yom Kippur.