Rediscover Ancient Egypt

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Date Last Updated: 28-Mar-2003

The Perfect Egyptian Calendar



The Ancient Egyptian calendar followed the Sothic year. This fact is clearly acknowledged in the Webster dictionary which defines the Sothic year as:


The Ancient Egyptians knew that the year was slightly over 365¼ days. The earth takes 365.25636 days to complete one revolution around the sun.

It should be noted that the chronology of 3,000 years of Ancient Egyptian history, by modern Egyptologists, was made possible only because the Ancient Egyptians followed the Sothic Year of slightly over 365¼ days, i.e. 365.25636 days.

The Ancient Egyptians were able to construct a monument with perfect precision, to match their perfect calendrical calculations. At the Abu Simbel Temple of Ramses II, is a statue of Ramses II, located among other statues at the back of its sanctuary, 180ft (55m) away from the only opening to the temple. The rays of the sun have illuminated his statue, next to Amen-Ra’s statue, on 22 February of each year for more than 3,200 years.
The difference between 365.25 days and 365.25636 days, over a span of 3200 years, is 20 days. If such a minute difference of 0.00636 days per year was not accounted for, the date of illumination of the statue would have changed from its original date many years ago. The long duration of the shrine illumination is only possible because of the accuracy of the Ancient Egyptian Sothic calendar that followed the heliacal rising of Sabt (Sirius)—the Dog Star.

The practical Ancient Egyptians used a calendar consisting of 12 months, each equal to 30 days.



The Egyptian months, grouped into the Ancient Egyptian’s three seasons


The adjustments needed to make a complete year, i.e. the difference between 365.25636 days and the 360 (30 x 12) days, were made as follows:

  1. The difference of 5.25 days comes at the end of the Egyptian year, by adding 5 days every year and an additional day every 4 years. The Ancient Egyptian Year currently begins (in 2003) on 11 September. The 5/6 extra days begin on 6 September.
  2. The difference of 0.00636 day (365.25636 – 365¼ days) for each year requires adding another day every (1/0.00636) 157¼ years, which the Egyptians continued to do until our present times. This is accomplished by adding an extra day every 157, 314, 471, and 629 year cycles.

The Egyptians’ advanced knowledge in astronomy, as reflected in their calendar, was acknowledged by the great Strabo (64 BCE–25 CE), who wrote:

They (the Egyptian priests) revealed to the Greeks the secrets of the full year, whom the latter ignored as with many other things...

When Julius Caesar came to Egypt in 48 BCE, he commissioned the astronomer Sosigenes (from Alexandria) to introduce a calendar into the Roman Empire. Sosigenes' work is best described in an excerpt from The Book of the Master of the Hidden Places by Marsham Adams:

He [Sosigenes] took no heed of standard or measure, of orbit or of sacred interval. But first he cut up the year into twelve unequal and unmeaning bits -- to say he divided it into portions is far too scientific an expression -- which rags bore indeed the name of the insulted moon, but of which that mighty measurer condescended to make no sort of recognition. And then he threw the "odd day" in along with the "odd month"; much as a child, who has broken his toy horse, glues a bit of the tail to the shortest of the legs, and calls aloud on creation to admire his handiwork.
This resulted in the Julian calendar of 365 days a year and 366 days every leap year. The Roman (Julian) calendar was literally tailored to be fit for a King. The first day of the year was the coronation day for the Egyptian King at the end of the annual rejuvenation Jubilee—the Heb-Sed Festivals [see Egyptian Mystics: Seekers of the Way, for more info].

However, because the Julian calendar did not take into account that the year is a bit longer than 365¼ days, the Gregorian calendar was introduced in 1582 CE to correct this error. The Gregorian calendar is still off by about one full day every 3,000 years.

In their attempts to have a different looking calendar than the Egyptian system, both the Julian and the Gregorian calendars fell short of the exact system, as developed by the Egyptians.

The difference between 365.25 days and 365.25636 days, from the time of the adoption of the Julian calendar to our present time, is 13 days. Such a difference explains the 13 day variation in the annual observations of numerous Christian festivals—between the Orthodox and non-Orthodox churches. The reason is that one group followed the accurate Egyptian calendar, while the other group followed the inaccurate Julian calendar.


Moustafa Gadalla


For more information about the Egyptian calendar, its history, and its influences on Egyptian life, read:
Egyptian Mystics: Seekers of the Way, by Moustafa Gadalla Egyptian Mystics: Seekers of the Way
by Moustafa Gadalla
192 pages, 5.5" x 8.5"
List Price: $11.95 USD (paperback)
$ 7.95 USD (eBook)
Egyptian Cosmology: The Animated Universe, by Moustafa Gadalla Egyptian Cosmology: The Animated Universe
by Moustafa Gadalla
192 pages, 5.5" x 8.5"
List Price: $11.95 USD (paperback)
$ 7.95 USD (eBook)
Egyptian Rhythm: The Heavenly Melodies, by Moustafa Gadalla Egyptian Rhythm: The Heavenly Melodies
by Moustafa Gadalla
240 pages, 5.5" x 8.5"
List Price: $14.95 USD (paperback)
$ 9.95 USD (eBook)




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