The other day, my friend told me about an Ancient Egyptian myth regarding the switch from the 360 to the 365-day calendar in Egypt. At the time, I just thought it was a cool story, but later realized that it was a perfect example of archaeoastronomy.
Before 4200 BCE, the Ancient Egyptian calendar year was 360 days long, composed of 12 months of 30 days each (Springer Link). This is because the year was based on the lunar cycle (Webexhibits), which at the time was considered to be 30 days long (it is now known to be 29.5). However, this lunar calendar failed to predict the annual flooding of the Nile river, which was a critically important event in Ancient Egyptian life. This spurred the development of a solar calendar with 365 days in a year, which is the earliest recorded 365-day calendar in human history. The five additional days are called epagomenal days (Global Egyptian Museum), which means “days within a solar calendar that are outside any regular month” (Collins Dictionary).
Due to not being incorporated into the normal months, these days were considered ominous, and their creation was immortalized in a mythological story characteristic of Ancient Egypt. Central to the myth was the sky goddess Nut, who became pregnant by the Earth god Geb (Lost Age Secrets). The supreme sun god Ra, worried that Nut and Geb’s offspring would usurp his rule, cursed Nut by preventing her from giving birth during any day of the year.
After hearing this, the god of wisdom, Thoth, took pity on Nut and Geb and challenged the moon deity Khonsu to a board game. Thoth proposed that should he win, he would be awarded a portion of the Moon’s light. Confident, Khonsu agreed, but Thoth was victorious. Thoth gave the light he won to Nut, and the shift in energy increased the Earth’s orbital time to 365 days. Since these extra five days were not included in the 360 days that Ra cursed, Nut was able to give birth to five children, one on each day. They were Isis, Osiris, Seth, Nephthys, and Horus. Thus, Thoth’s act of kindness to Nut and Geb explains Egypt’s transition to a more astronomically accurate solar cycle, although understandably still not as accurate as the 365.2422-day year we now recognize (The Washington Post).
This story made me think about the way myths grow and develop and the degree to which they are believed. I feel that my conception of ancient myths is similar to how many modern people conceive of religion. Many religious people believe that the stories described in, for example, the Bible actually happened in history. What about in the context of this Ancient Egyptian myth about the switch to a 365-day calendar? Were there people alive who understood that the calendar needed five extra days because the initial year calculations were incorrect, or did they believe that Thoth had just recently won his board game against Khonsu, causing their previous calendars to become incorrect? Was the myth an entertaining story to explain their new calendar, or a deeply held belief?
