Exploring the Implications of a Lunisolar Calendar in the Qur'an: A Contextual and Historical Analysis

I will focus on analyzing the verses exclusively based on what is written in the Qur'an, without traditional Islamic interpretations related to the calendar.

1. Verse 18:25 (the story of the sleepers in the cave):

The verse says:

"And they remained in their cave for three hundred years and added nine."

If we follow what is written, we notice that the Qur'an states that "they "added nine", and at this moment we do not know who these are, but what we know is that the plural is used here. This means that the writer does not claim that he added nine years but that it was done by them, some people.

The context of the verse does not explain exactly why "nine" was added, but a possible implication is the difference between lunar and solar years. If their lifespan lasted 300 solar years, it would amount to approximately 309 lunar years, which could be one way to understand this difference. However, the Qur'an does not directly explain this distinction, nor does it claim that adding nine years is the result of a different calendar – it remains open to interpretation.

2. Verse 17:12 ("That you may know the number of years and the calculation of time"):

The verse says:

"And We have made the night and the day two signs. Then We have made the sign of the night dark and the sign of the day bright, so that you may seek bounty from your Lord, and that you may know the number of years and the calculation of time."

This verse clearly connects the alternation of night and day with the calculation of years and time. There is no mention of the Moon, which could indicate a solar calendar, as the solar year depends on the alternation of day and night governed by the Sun.

3. Verse 10:5 (The Sun and the Moon for calculating years):

This verse says:

"He is the One who made the Sun radiant and the Moon a light and determined its phases so that you may know the number of years and the calculation of time."

Here it is clear that both the Sun and the Moon play a role in the calculation of time. The Sun is connected with light and days, while the Moon is associated with phases that are key for the months. The Qur'an implies here that both celestial bodies should be used for calculating years and time. What is important is that the Qur'an does not mandate exclusively a lunar or solar calendar but mentions both celestial bodies as tools for timekeeping.

This verse could imply an obligation to use both systems (the Sun for days and years, the Moon for months), which is characteristic of a lunisolar calendar. If we consider the Qur'anic verses that mention both the Sun and the Moon in relation to timekeeping, as well as the historical context of the Islamic calendar, there are valid reasons to suggest that a lunisolar calendar may be implied.

Qur'anic Context:

As we have observed, verses like 10:5 clearly indicate that the Sun and the Moon are tools for timekeeping. This combination is typical of lunisolar calendars, where lunar months are synchronized with the solar year through periodic adjustments (such as leap months). Also, verse 17:12 emphasizes the day and night as the basis for counting years, which leans more towards the solar aspect of the calendar.

This suggests that the calculation of years is tied to the Sun, while the Moon is mentioned as a means for determining months, making the calendar potentially lunisolar.

Historical Context:

The role of Caliph Umar in establishing the Islamic calendar seven years after the Prophet Muhammad's death also opens up an interesting discussion. It is true that the Islamic lunar calendar, as we know it today, was formalized during Umar's reign. Furthermore, some months carry names linked to seasonal events, such as Rabi al-Awwal ("First Spring"), which would indicate a seasonal (solar) connection. In a purely lunar calendar, where months are not tied to seasons due to the shorter lunar year, this seasonal connotation becomes meaningless as the months shift through all seasons.

Conclusion:

Considering the combination of Qur'anic verses and historical facts, the conclusion that the Qur'an implicitly points to a lunisolar calendar has a strong foundation. The Qur'an clearly mentions both celestial bodies for timekeeping, and the historical shift to a purely lunar calendar can be seen as a later development that is not necessarily rooted in the Qur'an itself. Argument regarding the seasonal names of some Islamic months in Umar's calendar also provides additional evidence that there might have been an original understanding of time that included solar elements, rather than solely relying on a lunar calendar.