This is a summary of Faraz’s article that can be found at Yaqeen Institute.

The Islamic calendar is a lunar calendar that plays an important role as the sacralization of time for Muslims. The Islamic calendar can be categorized into three unique elements. First, it is the marker of the migration of Prophet Muhammad ﷺ from Makkah to Medina, also known as the Islamic epoch (a fixed point that starts the era). Second, the Islamic calendar has four sacred months – al-Muḥarram, Rajab, Dhū al-Qa’dah, and Dhū al-Hijjah. Lastly, the Islamic calendar is a 12-month static lunar calendar in which the order and names of its lunar months are fixed. Allah says:

He is the One Who has made the sun a radiant source and the moon a reflected light, and precisely measured the moon by phases so that you may know the number of years and how to calculate time. Allah did not create this except with a purpose (Ḥaqq). He makes the signs clear for people of knowledge.

Allah also says:

Surely, the number of months ordained by Allah is twelve in Allah’s Record since the day He created the heavens and the earth—of which four are sacred. That is the upright religion  (al-dīn al-qayyim).

While the months and days of the calendar were well established, the companions still faced challenges in chronicling events on a yearly basis. When deeds and documents dated without the year came to government officials, it was unknown if the year documented was referring to the previous or current year; and even if documents came with the year written, the non-static epoch caused confusion. For example, if the year ten was written, was this ten referring to ten years after the Battle of Badr or after the migration of the Prophet? With this tabula rasa, they were forced to decide on a standard Islamic epoch to solve the dilemma.

Infamous events used as epochs was the conventional method throughout human history. In his book al-Muntaẓim fī Taʾrīkh al-Mulūk wa al-Umam, Ibn al-Jawzī (d. 597 A.H.) references Al-Sha’bī (103 A.H.) summarizing that mankind’s first epoch was the descent of Adam, then the rescue of Noah from the flood, and then the cooling of the fire in which Abraham was thrown into. Moreover, the Scythian monk Dionysius Exiguus (544 C.E.) introduced the method of counting years from the birth of Jesus which is used in the Gregorian calendar, anno Domini (A.D.) meaning “in the year of the lord”. Preceding that, the Romans would use years of Roman consuls, the regnal years of emperors, and the 15-year tax assessment cycle as their static epoch. 

Epochs were also used by the pre-Islamic Arabs. For example, they used the death of Ka’b bin Luʾayy, year of the elephant (ʿĀm al-Fīl), and Ḥarb al-Fijār as multiple epochs. This systemization continued into the caliphate of ʻUmar ibn al-Khaṭṭāb (23 A.H.) until the companions came to a consensus on using the migration of the Prophet ﷺ (hijra) as the Islamic epoch. In his historical chronicle Tārīkh al-Rusūl wa al-Mulūk, Al-Ṭabarī (310 A.H.) mentions a few narrations that led to the advent of the Islamic epoch:

Maymūn bin Miḥrān (117 A.H.) narrates: A legal document for a deed arrived to ‘Umar which had the month of Shaʿbān written on it. ‘Umar asked: Is this the Shaʿbān of last year or this coming year? Then he said to the companions: Let us determine an epoch for the people to use. Some suggested using the Roman calendar but others opposed arguing that they used the era of Dhu Al-Qarnayn as their epoch and that it was outdated. Others suggested to base it off the Persian system, however this was opposed as every new king ousted the epoch of the previous king and was too volatile of a calendrical system. Then they gathered and asked: How many years did the Prophet ﷺ stay in Medina? They answered ten and then it was determined that the epoch was the migration of the Prophet ﷺ.

For the companions, the Prophet’s migration was the spiritual and physical establishment of the first Muslim community as Dr. John Esposito succinctly states:

The importance of the hijra is reflected in its adoption at the beginning of the Islamic calendar. Muslims chose to date their history from neither Muhammad’s birth nor his reception of the first revelation in 610, but from the creation of the Islamic community (umma). The community, as much as the individual, was to be the vehicle for realizing God’s will on Earth.

In brief, the Islamic calendar is not only a 12-month static lunar calendar with four sacred months, but also a marker of Islamic identity by virtue of the institutionalization of the first Muslim community 1442 years ago.

Nasī’ and Sacred Months

The second component of the Islamic calendar is the four sacred months as Allah says:

Surely, the number of months ordained by Allah is twelve in Allah’s Record since the day He created the heavens and the earth—of which four are sacred. That is the upright religion. So do not wrong yourselves during these months and fight the associators all together, as they fight you all together, and be sure that Allah is with the God-fearing.

In addition, the Prophet ﷺ said in his farewell sermon:

Time has come back to its original state which it had when Allah created the Heavens and the Earth; the year is twelve months, four of which are sacred. Three of them are in succession; Dhul-Qa’da, Dhul-Hijja and al-Muḥarram, and [the fourth being] Rajab Muḍar which stands between Jumādā (Thānī) and Sha’bān.

Three of the four sacred months are in succession, Dhū al-Qa’da and Muḥarram – a month before and after Ḥajj – and Dhū al-Hijja. For the Pre-Islamic Arabs Ḥajj was not only a pilgrimage but also the annual epicenter for trade and information. Thus, the three consecutive months are sacred because it allowed people to travel to perform Ḥajj and return safely as Ibn Kathīr states. As for Rajab, the reason it is sacred is because those who traveled from afar could come earlier in the year to set up for pilgrimage and leave at a later time safely. Protecting travelers to and from Ḥajj was of the utmost importance and any strife or bad blood amongst tribes was to be put on hold and resumed at a later date effectively prohibiting any fighting. 

Nasī’ was the reallocation of sacred months with various motives. Ibn ‘Abbās (68 A.H.), Abū Manṣūr al-Azharī (370 A.H.) and others relate that the pre-Islamic Arabs would switch Muḥarram and Ṣafar to avoid three consecutive sacred months. Others suggest that they would rename Muḥarram as Ṣafar resulting in two Ṣafars. Mujāhid (102-4 A.H.) states they would perform Ḥajj in the same unique month for two years at a time. For example, they would perform Ḥajj in the month of Dhū al-Hijjah for two years, then in the month of Muḥarram for two years, et cetera. However, there seems to be little evidence supporting this. Abū Mūsā al-Ashʿarī (48 A.H.) states that every two years they would add a 13th leap month resulting in two consecutive months of Ṣafar. The Persian polymath Al-Bīrūnī (440 A.H.) states that they would add a 13th leap month every three years. The addition of a 13th month was an attempt to sync the lunar calendar with the seasons of the year, also known as intercalation which will be explained in more depth.  

Thus, the Muslim scholars have interpreted  nasī’ in two ways: an intentional reallocation of sacred months which the pre-Islamic Arabs may have used for political influence, and an incidental reallocation of sacred months due to the inserting of leap months, a method practiced by the Jews. Below is an illustration of the different opinions of nasī’.

Political Influence and the Lunar Calendar

It is difficult to imagine a society in which dates are unknown to the masses or altered. Our lives have been carefully constructed and augmented by the modern calendar, and with globalization, any change would cause pandemonium. However, it was commonplace for calendars to be used as a tool for power and manipulation throughout history.

For example, in the early days, the Roman calendar contained a list of dies fasti, sanctioned dates which governing and societal organizations would conduct business in. These dates were not available to the public; rather, they were controlled by Roman kings and the aristocratic patrician class. For the first few centuries the priests and aristocrats kept the calendar a secret among themselves which gave them an advantage over the commoners in conducting business and controlling the religious and social structure that governed Roman life.

In Arabia, Banū Kināna was an influential Arab tribe responsible for the fair of Majanna, the worship of the idol al-’Uzza, and determining the reallocated months (nasī’). They would appoint one with the title of Qalammas who would implement the reallocation of months during Ḥajj season. As tribes were departing from Minā, Qalammas would say: “I am the one whose decision will not be overturned!” The Arabs would then approach him and say: “Postpone Muḥarram and replace it with Ṣafar!” He would then switch the months and those at Ḥajj would go back to their homes and inform their families of the change. This great responsibility Banū Kināna inherited gave them political influence in conducting trades and fairs, controlling the cycle of pilgrimages and influencing tribal wars, so much so that any threat would result in retaliation.

Due to this volatile tribal polity, Islam sought to institutionalize systems of justice. One of these methods was computing the months by the sighting of the moon. Unfortunately, moon sighting in recent times has been reduced to a cause célèbre every Ramaḍān and can lead to fissures in a community. While there is merit in discussing its juristic details and implementation, it can at times overshadow the greater wisdom. Long throughout history abuse of power and control over the calendar left the rabble folk at the mercy of the strong. As Banū Kināna would hold a tight grasp over the calendar, the Islamic ruling of moon sighting redistributed the responsibility to the masses. It acted as a divine system of checks and balances as the moon cannot be hidden from the masses, it is observed by all, and it prevents those in power from exploiting and monopolizing the calendar. As long as just, sane, adult Muslims bear witness that they saw the moon, the ruler is to take their testimony into account. Islam does not forego authority, but it brilliantly provides a natural checks and balances system which is often forgotten. 

Intercalation through Imitation

The lunar calendar falls ten to eleven days behind the solar calendar every year which results in the seasons desynchronizing with the lunar months. To adjust for this, they would add a 13th month every three years to make up for the difference so that the seasons match the months annually, also known as intercalation. One reason to believe the Pre-Islamic Arabs were intercalating is shown by the names of the months. For example, the month of Ramaḍān was named due to scorching heat and the month of Jumādā was named referring to water freezing. Thus, to name lunar months based on seasonal weather is reason to suggest that there was some understanding of intercalation when the months were first named. 

Another motivating factor to intercalate was that it provided ease in scheduling of fairs and for harvesting crops. Hideyuki aptly states: “In pre-Islamic Arabia, a cycle of fairs going around the Peninsula clockwise had been established as being the most favorable for trade. Therefore, we may conclude that the 12-month lunar calendar was adjusted periodically by inserting a leap month to ensure the fairs occurred in the proper seasons.”

The question remains, how did the pre-Islamic Arabs learn to intercalate? The polymath Al-Bīrūnī states that “they learned intercalation from Jewish people in the area. It was 200 years before the hijra. This was called nasīʾ because the beginning of a year was postponed by one month every two or three years.” As the Jews migrated to the Arabian Peninsula they brought along their calendar which comprised of a complex intercalation by incorporating a 13th month in the following 19 year cycle: 3rd, 6th, 8th, 11th, 14th, 17th, and 19th year. Observing the Jews the Arabs produced an unrefined intercalation that inserted a leap month every two or three years. Intercaltion did provide ease to the pre-Islamic Arab lifestyle, but at its core it was an attempt to imitate (tashabbuh) the Jewish calendar.

Present Day

It is difficult to claim that in the present day we have reached a level of impermissible imitation. The names of the months, its order and the religious holidays associated with the Islamic calendar have remained unaltered. And while the Gregorian calendar has been the dominant calendar used around the world, benefiting from it as a tool of communication adjacent to the Islamic calendar is not inherently wrong. 

However, one cannot deny that it has also led to a spiritual comatose as a result of a covert colonization. The predecessors were aware of any motives to shift society away from the Islamic calendar and would speak vociferously against it. For example, Ibn Taymiyya states in iqtiḍā’ al-ṣirāt al-mustaqīm: “As for foreign talk and naming their months with foreign names, Abū Muḥammad al-Kirmānī (280 A.H.) said: I said to Aḥmad ibn Ḥanbal (241 A.H.): “[Did you know] the Persians have days and months that they call by names that are not known [to the Islamic calendar]?” Aḥmad extremely despised this.

If simply changing the names of the Islamic months by fellow Muslims angered Aḥmad ibn Ḥanbal, and tampering with the calendar led to its prohibition by God in the Quran and His messenger in his farewell sermon, then a fortiori the decline of the Islamic calendar in favor of the Gregorian calendar whose epoch is inspired by the birth of Jesus to whom they attribute divinity to is perturbing and at least cause for concern. 

It is this lax behavior which has diminished the role of the Islamic calendar in the lives of Muslims and in Muslim countries. For example, the Ottoman empire at its inception standardized the Islamic calendar but by the 17th century under Sultan Mehmed IV, the treasurer, Hasan Pasha, suggested to implement the Julian calendar only for fiscal matters as a way to accommodate the surrounding countries. By the mid 19th century after the Tanzimat reforms it became the official calendar for all civic matters. Following the defeat of World War I and the Treaty of Sevres, on December 26, 1925 the Islamic Calendar lost its validity with the “Changing the Inception of the Calendar” law when the official calendar was changed to the Gregoiran calendar and has been valid up to the present day. This decadence was the result of a vacuum of Imam Aḥmad-esque heros standing up to this atrophy. From this one could even argue that a condition of an Islamic empire being legitimate is to have a standardized Islamic calendar.

It is an understatement to say that the Islamic calendar has waned and become secondary in the lives of Muslims across the world. The Islamic calendar was a casualty in the diaspora of the Muslim community in the early 20th century espoused by leaders imitating non-Muslims. As Ibn Khaldūn states in his Muqaddimah: “The vanquished always want to imitate the victor in his distinctive mark(s), his dress, his occupation, and all his other conditions and customs.” The Prophet ﷺ said: “The Hour will not occur as long as anyone says: Allah, Allah.” Surely before this sign, the Islamic calendar, its months and importance will utterly be forgotten. The least we can do is resist these temptations and reinsert the Islamic calendar into our daily lives.