The Number 41 and Giza Architecture

There was something about the number 41 at Giza during the Old Kingdom: The cemetery to the west of the Great Pyramid had 4 master-planned communities of the dead. The G4000 cemetery had 41 mastabas next to the main mastaba G4000, the tomb of Hemiunu, the alleged architect of the Great Pyramid. The width of Hemiunu's tomb was 41 cubits (see my paper at Two boats were discovered south of the Great Pyramid. The eastern boat was hidden under 41 blocks of stone. The Queen chamber inside the Great Pyramid is 41 cubits above ground and the King Chamber is 2 x 41 = 82 cubits above ground (this was first noticed by John Legon. See What was it with the number 41?

Satellite Image of the Giza Plateau, Cairo Museum. The graphic below is from The Cheops Boats by Mohammad Zaki Nour, Mohammad Salah Osman, Zaky Iskander, and Ahmad Youssof Moustafa

Well there is a mystical line opening a medical text written some 1200 years later. There is a clue in this text:


A book fell from heaven and it was noticed when the Moon shone on it. It was taken to Khufu/Cheops. From another papyrus, the Westcar Papyrus, legend has it, Khufu was looking for the number of chambers in the sanctuary of Thoth (the Moon). So there was something about the Moon and Khufu. It turns out that 41 is almost exactly the number of days the Moon will spend to go around Earth one and one-half times on its orbit: 27.3216 days x 1.5 = 41 days. What we think of when we think of a month is a period of 29 to 30 days. This is a synodic month. It tracks the shape of the Moon to repeat itself. The original lunar calendar of the ancient Egyptians was based on this period according to Richard Parker (see calendars of Ancient Egypt at The sidereal month, on the other hand, has to do with the Moon's position on its orbit, not its shape as it appears to us. The sidereal month is the Moon "striding" on the map of the stars made up by the stars (our Zodiac constellations) near the path of the Sun and Moon, the ecliptic.

And so it is possible that the sidereal period, not the synodic period, of the Moon/Thoth was on Khufu's mind when he had his pyramid city of the dead built. The Edfu Temple has a great passage about Thoth and numbers to build the primordial temple of Egypt:

Behold the cubit of the Architect proclaimed Ra. One hundred-and-ten because it strides right, ninety because it gives a stable shine. Cubit Arise! said the falcon and so arose The Cubit.

Clearly, 110 cubits had to do with striding as in the Moon strides along the ecliptic in a sidereal period and 90 cubits had to do with shining as in synodic period. 110 is 4 x 27.5. In days, 27.5 is what a human eye can discern the Moon to take to come back to a certain position on the ecliptic. The Great Pyramid's base is 64 x 27.5 cubits. The finer measure, 41 cubits, was used six times in the interior design (see John Legon). This is what Khufu was likely looking for: He wanted to encode the Moon's sidereal period in the architecture of his horizon, his pyramid. But this information rested with the astronomers of his time, the priests of Heliopolis and Hermopolis, the cities of the Sun and Moon.

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