The Origins of the Islamic Calendar — The Hijra
Religious and Historical Study
In its lexical sense, the Arabic term Hijra denotes leaving a particular place or state and relocating to another. In Islamic history, the Hijra refers primarily to the migration of the Prophet Muhammad from Mecca to Medina (Yathrib). This event took place in 622 CE and is conventionally regarded as the starting point of the Islamic historical era.
For a prolonged period in Mecca, the first Muslims were subjected to pressure, persecution, and severe hardship. Their ability to practise their faith freely and to proclaim Islam became increasingly restricted. At the same time, the threat to the life of the Prophet posed by the Meccan polytheists continued to intensify.
After the people of Medina embraced Islam and invited the Prophet to migrate to their city, the Muslims began relocating to Medina. By the command of Allah, the Prophet himself also undertook the Hijra. This migration made possible the secure institutional development of the Muslim community and the emergence of Medina as the centre of the new Islamic society.
In pre-Islamic Arab society, it was customary to designate years by reference to significant historical events. For example, the year of the Prophet’s birth came to be known as the “Year of the Elephant”, in reference to the famous expedition of the army of the elephant. The year in which Muhammad’s prophetic mission commenced was known as the “Year of the Biʿtha” (the commencement of his prophetic mission). The Prophet’s migration from Mecca to Medina marked the beginning of a new stage in the history of Islamic society. Consequently, the Hijra was subsequently adopted as the starting point of the Muslim historical era.
The formal establishment of the Hijra as the starting point of the Islamic calendar took place during the caliphate of ʿUmar ibn al-Khattab, in the seventeenth year of the Hijra, corresponding to 638 CE. According to a well-known account preserved in the Islamic historiographical and calendrical tradition, an official system of dating was being discussed at the time. Various events were proposed as possible points of reference. It is reported that Imam ʿAli proposed adopting the Hijra as the beginning of the historical era. Since the Hijra symbolized the transition of the Muslim community from the Meccan period to the Medinan period and marked the emergence of the Muslims as a unified political and social community, this proposal was accepted. (Al-Tabari, Tarikh al-Rusul wa al-Muluk, vol. 4, p. 388; Ibn al-Athir, Al-Kamil fi al-Tarikh, vol. 2, p. 16.)
The Prophet’s migration from Mecca to Medina took place in the month of Rabiʿ al-Awwal. Historical sources report that the Prophet left Mecca on the first of Rabiʿ al-Awwal and arrived at Quba, a locality near Medina, on the eighth. He remained there for several days and began the construction of what is regarded as the first mosque established in the history of Islam. On the twelfth of Rabiʿ al-Awwal, he resumed his journey towards Medina and arrived there on the sixteenth of the month.
The Islamic religious calendar is a lunar Hijri calendar (al-Hijri al-Qamari). It is based on the lunar cycle and consists of twelve months. Accordingly, when the expression “Hijri calendar” is used in Islamic religious texts, it generally refers specifically to the lunar Hijri calendar.
The lunar Hijri calendar consists of twelve months: Muharram, Safar, Rabiʿ al-Awwal, Rabiʿ al-Thani, Jumada al-Awwal, Jumada al-Thani, Rajab, Shaʿban, Ramadan, Shawwal, Dhu al-Qaʿda, and Dhu al-Hijja. Naturally, these names, as well as the lunar months themselves, were already in use in Arabia prior to the emergence of Islam.
The lunar months consist of either 29 or 30 days. Consequently, a lunar year is approximately 10–12 days shorter than a solar year. As a result, the months of the Hijri calendar, whose beginnings are determined according to the lunar cycle, shift each year in relation to the solar calendar and occur approximately 10–12 days earlier than in the preceding solar year.
The Holy Qur’an states: “Indeed, the number of months with Allah is twelve months in the register of Allah, from the day He created the heavens and the earth…” (al-Tawba, 9:36)
Another verse points to the role of the Sun and Moon in the reckoning of time: “It is He who made the sun a radiant light and the moon a reflected light and determined for it phases, so that you may know the number of years and the reckoning of time.”
(Yunus, 10:5)
For this reason, in Islam the lunar Hijri calendar has particular significance in determining the period of fasting in Ramadan, the performance of Hajj, the calculation of Zakat, and the observance of other religious obligations.
An important distinction must also be made between the lunar Hijri calendar (Hijri Qamari) and the solar Hijri calendar (Hijri Shamsi).
The Hijri Shamsi calendar is not a second Islamic calendar that was created directly at the time of the Prophet’s Hijra. In the Islamic world, particularly in the territory of present-day Iran, ancient solar calendrical traditions existed that predated Islam. In various forms, these traditions continued to be used throughout the Islamic period.
Over the subsequent centuries, the solar calendar underwent further development and refinement. Under the Seljuk ruler Malik Shah, a group of astronomers developed the Jalali calendar. Its implementation began on 9 Ramadan 471 AH, corresponding to 15 March 1079 CE.
In this calendar, the beginning of the year was associated with spring, the vernal equinox, and Nowruz. Over the following centuries, the Jalali calendar underwent various modifications and refinements.
Finally, in 1925, during the reign of Ahmad Shah Qajar, the solar Hijri calendar (Hijri Shamsi) was officially established. Its system of reckoning years was likewise linked to the Hijra of the Prophet Muhammad; that is, the Hijra from Mecca to Medina was adopted as the beginning of its historical era.
Namiq Babakhanov
Baku — 2026