The Islamic calendar employs the Hijri technology whose epoch turned into mounted as the Islamic New 12 months of 622 ad/CE. all through that year, Muhammad and his followers migrated from Mecca to Yathrib (now Medina) and set up the primary Muslim community (ummah), an occasion honored because the Hijra.
inside the West, dates in this period are generally denoted AH (Latin: Anno Hegirae, “in the year of the Hijra”) in parallel with the Christian (ad), common (CE) and Jewish eras (AM). In Muslim nations, it is also once in a while denoted as H from its Arabic shape (سَنة هِجْريّة, abbreviated هـ). In English, years prior to the Hijra are reckoned as BH (“earlier than the Hijra”).The contemporary Islamic 12 months is 1440 AH. within the Gregorian calendar, 1440 AH runs from about eleven September 2018 to 30 August 2019.[a]
For vital Arabia, in particular Mecca, there’s a lack of epigraphical proof but information are determined within the writings of Muslim authors of the Abbasid era. Inscriptions of the historic South Arabian calendars display the usage of some of neighborhood calendars.
at the least some of these South Arabian calendars observed the lunisolar machine. each al-Biruni and al-Mas’udi propose that the historical Arabs used the equal month names as the Muslims, though in addition they report other month names utilized by the pre-Islamic Arabs.The Islamic culture is unanimous in mentioning that Arabs of Tihamah, Hejaz, and Najd outstanding between two varieties of months, accredited (ḥalāl) and forbidden (ḥarām) months.
 The forbidden months had been 4 months in the course of which fighting is forbidden, indexed as Rajab and the three months across the pilgrimage season, Dhu al-Qa‘dah, Dhu al-Hijjah, and Muharram.
. facts approximately the forbidden months is likewise found in the writings of Procopius, where he describes an armistice with the jap Arabs of the Lakhmid al-Mundhir which took place inside the summer of 541 ad/CE.
but, Muslim historians do now not hyperlink those months to a selected season. The Qur’an hyperlinks the four forbidden months with Nasī’, a phrase that literally way “postponement”.[5
] consistent with Muslim culture, the choice of postponement become administered by the tribe of Kinanah, by way of a man known as the al-Qalammas of Kinanah and his descendants (pl. qalāmisa).exclusive interpretations of the idea of Nasī’ were proposed. some scholars, each Muslim and Western, hold that the pre-Islamic calendar utilized in relevant Arabia turned into a in basic terms lunar calendar similar to the cutting-edge Islamic calendar.
in keeping with this view, Nasī’ is related to the pre-Islamic practices of the Meccan Arabs, where they could regulate the distribution of the forbidden months inside a given yr without implying a calendar manipulation.
This interpretation is supported with the aid of Arab historians and lexicographers, like Ibn Hisham, Ibn Manzur, and the corpus of Qur’anic exegesis.