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An Upside-Down History of the World [Japanese]
[Chapter 3] The Origins of Monotheism

Part 1: A Human Hypothesis
26 Descendant of Adam

Islam’s sacred text, the Koran, is believed to be a revelation from God, Allah.

If you’ve read the previous installment, you know one of the major differences between Christianity’s New Testament and Islam’s Koran. Since Christianity teaches that Jesus is God, the Christian authors of the New Testament detail, from their own perspectives, the life and teachings of Jesus Christ. The gospels of Matthew, Mark, Luke, and John are biographies of sorts.

The Koran is different. It is considered to be a revelation from God (Allah).

Almost nothing is known about how or where Muhammad (Muhammad ibn ̒Abd Allāh ibn ̒Abd al-Muṭṭalib) received this “recitation” from God. Even the word Mecca, the name of the Islamic holy land, makes no appearance in the Koran.

It’s why biographies of the “last and greatest prophet” Muhammad were compiled relatively early on in Islam’s existence. And since Muhammad is through and through human, these biographies are not, technically speaking, scripture.

But as one of the oldest, most definitive biographies of Muhammad, Ibn Ishaq’s The Life of Muhammad is, to many, as sacred as any biblical text.

The Holy Land, Moved

Ibn Ishaq was born in around 704 in Medina, a city on the Arabian Peninsula known today as part of Saudi Arabia. During Ibn Ishaq’s life, Medina was known as Yathrib. Yathrib was renamed Medina in 662 when it’s believed Muhammad and his followers took their famous journey, the Hijrah, to the city to escape persecution. The year 662 also marks the beginning of the Islamic calendar.

Keep in mind, the Islamic calendar is purely lunar. Months in the lunar calendar reflect the lunar cycle, making it possible to know the date by simply looking up at the night sky. A full moon signifies the fifteenth, and a sky with no visible moon (of course unobstructed by clouds) can mean either the first day of the month (a new moon) or the last day of the month (the last day of the previous month).

But there’s also a problem. A complete cycle of the moon takes approximately 29.5 days, which means multiplying this number by twelve yields only 354 days. And as you already know, it takes Earth about 365 days to complete one orbit around the sun. If you apply the lunar calendar to a twelve-month year, the months and seasons begin to drift. With the solar calendar, which divides 365 days into twelve equal parts, the northern hemisphere experiences summer and winter in August and December, respectively. But an eleven-day gap arises between the solar and lunar calendars, meaning that, with the passage of several years, August becomes first fall and later winter. To adjust for this gap, a number of ancient cultures devised a number of solutions, the most prevalent of which was the ubiquitous lunisolar calendar. Its time-telling method creates an embolismic year in which a thirteenth intercalary month (leap month) is added once the eleven-day gap equates to a single calendar month. The adjustment of solar years with lunar months is what makes this lunisolar calendar different from a pure solar calendar.