Sothic cycle

The Sothic cycle is the extended calendar that the Egyptologist Eduard Meyer invented in 1904 in an attempt to standardize the dates given on Egyptian documents (carved in stone or written on papyrus) and produce a unified chronology of ancient Egypt.

Basis of the cycle
The star called Sirius, or the "Dog Star," is the brightest star in the southern or tropical sky at night. Manetho, in the third century BC, caught multiple mentions of the phrase peret Sopdet, or literally, "rising of Sirius," in the documents that he examined. Sopdet is the Egyptian word for "Sirius." The Greek word is Sothis.

Richard Lepsius, in 1858, first suggested that the phrase peret Sopdet referred to a regular astronomical event. Meyer, in 1904, constructed a long-range calendar based on the following observations:


 * 1) The Egyptians observed a civil year exactly 365 days long, with no leap years, computed as 12 months of 30 days each, plus five extra days. Thus it would gain a day every four years, as Julius Caesar would later reckon.
 * 2) This year made no attempt to synchronize with the moon and, by gaining a day every four years, maintained no synchrony with the sun, either.

Meyer calculated that Sirius would make a heliacal rising (that is, first be visible shortly before dawn during any given year) on the Egyptian New Year's Day every 1,460 years--that is to say, four times 365 years, at which time the calendar would realign with the seasons. Meyer then assumed that the Egyptians used this extended calendar as their actual civil calendar. Finally, he fixed the most recent "rising of Sothis" as having occurred in AD 140. He based this fixation entirely on a writing by Censorinus, who allegedly had written that a heliacal rising of Sirius did fall on the Egyptian New Year in that year.

Projecting backward (and assuming that Censorinus was correct and that Meyer understood him correctly), Meyer calculated prior Sothic years as having occurred in 1320 BC, 2780 BC, and 4240 BC. Meyer then supposed that 2780 BC occurred in Manetho's Fourth Dynasty, and that the Sothic calendar was already in use at the time. On that basis, he concluded that the year 4240 BC saw the invention of the Sothic calendar and was also the oldest fixed date in recorded human history.

Early Criticism and Ultimate Acceptance
Meyer's system won instant acclaim, because it promised to bring order out of the chaos that prevailed among Egyptologists prior to the publication of his thesis. Some Egyptologists who were contemporary with Meyer rejected his thesis because they found it violative of a number of synchronies, and also based upon too many ad hoc assumptions. Nevertheless, the Sothic cycle theory withstood its critics and remains today the basis for all conventional dating of the various Egyptian monarchs.

Modern Criticism
Today, the Sothic cycle has come under renewed criticism, on a number of grounds:


 * 1) Extremely problematic synchrony between early Egypt and other nations with which Egypt is said to have had contact, been at war, etc. Some critics even assert that such synchrony is utterly lacking in definite, incontrovertible markers of time.


 * 1) Lack of mention of the Sothic cycle or any calendar based thereon in Egyptian literature. Mackey and others assert that Meyer based his theory entirely on non-Egyptian classical sources.


 * 1) Lack of mention of any epoch for the Sothic cycle in Egyptian literature.


 * 1) The arbitrary assumption that the Egyptians would never have changed their civil calendar in several millennia. Were this the case, the Egyptians would be virtually the only great power ever so to act. In particular, the Egyptian literature nowhere mentions whether the extra five days (added to 12 times 30 = 360 days) were always part of the calendar.


 * 1) The assumption that the Egyptians would somehow have known about the 1460-year period of Sirius as far back in time as 4240 BC, more than a thousand years before Pharaoh Menes is said to have brought about a unification of Egypt in--according to conventional dating--3100 BC.


 * 1) Lack of precision in the original astronomical dates used. This is by far the most important criticism of all. Astronomical dating is the most reliable way to date past events--so long as the astronomical records are precise, unambiguous, and incontrovertible. Critics of Sothic dating point out that:


 * That "Sothis" means "Sirius" is only an assumption, based on the interpretation of a work (Manetho's History of Egypt) of which only fragments survive today.


 * The first year of a "Sothic Great Year" has three possible beginnings, because the new year would not actually fall out of synchrony with Sirius (if Sirius is the star in view) until four years had passed.

In addition to the above, critics have pointed out that:


 * 1) Most Sothic cycle proponents still adhere to Manetho's original assumption that his thirty "dynasties" (Dynasty Thirty-one refers to the Ptolemies and the Cleopatras after the death of Alexander the Great). Yet the monumental evidence--that is, evidence derived from the monuments of the various Pharaohs--clearly and convincingly shows that many dynasties ruled in parallel, perhaps in different parts of Egypt at the same time, rather than in a strict series.


 * 1) The Sothic cycle allows only a hundred years for the Second Intermediate Period, also known as the Hyksos Era. Josephus gives a figure of 511 years. The available monumental evidence supports the larger of these two figures--and in fact, Josephus cites Manetho himself for that figure.

Finally, young earth creationists reject any scheme that would suggest or imply that the Egyptian state began any earlier than the Global Flood--which occurred no later than 2243 BC and possibly as early in time as 2563 BC.

Current Status
The academic community appears confused as to whether to accept the Sothic cycle or not. One of the most authoritative conventional sources seems at once to condemn and yet to rely on the Sothic cycle as a foundation for Egyptian chronology. Specifically:"The most significant advance made in the study of ancient Egyptian chronology in recent years is the repudiation by Neugebauer and others of an astronomical origin for the Egyptian civil calendar and, as a corollary, the elimination of the so-called Sothic Cycle as a factor in dating the earliest periods of Egyptian History."

And yet:"For the fixing in time of the Egyptian Middle Kingdom and the periods preceding it, the key date is the seventh year of the reign of King Sesostris III of the Twelfth Dynasty. In this year, a helical rising of the star Sothis (our Sirius) was recorded on 16. VIII of the 365-day civil calendar, a fact which, thanks to the regular displacement of this calendar, in relation to the true astronomical year, allows the year in question to be placed between 1876 and 1864 BC, with every probability favoring 1872 BC."

The two paragraphs are clearly contradictory--for as Michael Sanders points out, how can a source condemn the Sothic cycle as unreliable and yet in the same volume use it to fix an epoch?

Despite the criticism, conventional Egyptologists still use the Sothic cycle to compute their dates--primarily because they recognize that, without the Sothic cycle, Egyptian chronology becomes exactly what Heinrich Otten called it in 1973: "a rubber chronology."