MANETHO - EGYPTIAN CHRONOLOGY

Old Kingdom - Manetho's Dynasties

Much of Egyptian Chronology is based on Manetho's list of the Dynasties of Kings, but this too only second-hand, primarily through Julius Africanus and Eusebius. Indeed, Manetho may be a description of the subject [Latvian MAINITU "changes"] rather than an author at all. Still, we use Manetho's name to refer here to what we call "Manetho's Sums" for the Old Kingdom. These sums are quite unusual, since the individual lengths of the reigns of pharaohs DO NOT equal the subsequent sums appended as sums at the end of each Dynasty by Julius Africanus.

Discrepancies in Manetho's Sums

The total length of the actual individual reigns for the Old Kingdom is 1480 years - when we add them individually. But the sum of those reigns as actually given by Africanus is 1497 years - in the same document! Surely Manetho could add, or is there an unknown intercalation in his chronology?

Here are Manetho's OWN numbers for Dynasties 1 through 6
(individual actual sums per Dynasty plus sums as appended by Manetho)
263 (253), 304 (302), 214 (214), 284 (277), 218 (248), 197 (203).

In other words, for the first dynasty, the actual sum of reigns is 263 years but Africanus sums it as 253. For the second dynasty, the actual sum is 304, which Africanus sums as 302. For the third dynasty, there is agreement. For the fourth dynasty, the actual sum is 284 but Africanus gives 277. For the fifth dynasty, the actual sum is 218 but Africanus writes 248. For the sixth dynasty, the actual sum is 197 but Africanus has 203.

These numbers are strange - no one can add that badly, so that the constant discrepancies must be intentional, which chronologers have inexplicably ignored. The answer appears to be found in adjustment intercalations for the Sothic Year.

The Sothic Year

The Sothic Year (heliacal rising of a star coincident with the start of the solar year) is 1460 years, after which time one year is added to this total to make 1461 years to bring the solar year into synchronization with star time - which is called the tropical year. The Sothic Year can be understood if one takes the solar year as 365 days and a tropical star year as 365.25 days. Without intercalation (correction) the solar year lags . 25 days behind the tropical star year each year so that it takes 1460 years until the systems are again synchronized, with a difference of 1 full year. Egyptologists think the Sothic Year was tied to Sirius (Sothis) but this was originally surely not so, since Sirius apparently became important only with the Papyrus of Ebers. As Eduard Meyer wrote, no Egyptian source ties the Sothic Year to Sirius.

The same basic system is used to intercalate a leap day every 4 years, i.e. 4 x 365 days = 1460 days but 4 x 365.25 days = 1461 days, which is why we have leap years and add February 29 every 4 years to our calendar. In 1460 years (the Sothic Year) we thus add 365 such leap days or one full year.

The Dynasties 1 through 6 add up according to Manetho on the one hand to 1480 years and on the other hand to 1497 years, so that these sums surely represented Sothic year-days of 1460 days viz. years, with a possible precessional intercalation of either 20 day-years or 37 day-years. Such an intercalation would have been required in any case for astronomical data since Manetho calculated the figures thousands of years after the fact.

Manetho had to make Adjustments for Precession

We know that precession of the solstices and equinoxes within the stars advances one degree-day of stars in 72 years so that 37 days x 72 years = 2664 years. Hence, the Old Kingdom dynasty must have started about 2736 years prior to Manetho's writing (i.e. 37 degree-days of heliacal risings had been "lost"). If we presume, however - as the evidence of 76 kings at Abydos indicates - that the Pharaonic astronomers and Manetho used the Metonic 76-year period (4 x 19 Metonic Cycles) as their precessional measuring stick, then 37 x 76 years = 2812 years and 2812 years minus the date of December 25, -3116 (3117 BC) as the start of the Old Kingdom gives a date of -304 (305 BC) as the date from which Manetho calculated his lists of Pharaonic kings, and this date of 305 BC corresponds with current dating of Manetho's writing.