Journal of Egyptian History �0 (�0�7) 69–�08 brill.com/jeh A New Astronomically Based Chronological Model for the Egyptian Old Kingdom Rita Gautschy University of Basel [email protected] Michael E. Habicht University of Zurich and Flinders University, Adelaide [email protected] Francesco M. Galassi University of Zurich [email protected] Daniela Rutica University of Marburg [email protected] Frank J. Rühli University of Zurich [email protected] Rainer Hannig University of Marburg [email protected] Abstract A recently discovered inscription on an ancient Egyptian ointment jar mentions the heliacal rising of Sirius. In the time of the early Pharaohs, this specific astronomical event marked the beginning of the Egyptian New Year and originally the annual return of the Nile flood, making it of great ritual importance. Since the Egyptian civil calendar of 365 days permanently shifted one day in four years in comparison to the stars due * This work was supported by grants of the Mäxi Foundation and the Cogito Foundation. © koninklijke brill nv, leiden, ���7 | doi �0.��63/�874�665-��340035Downloaded from Brill.com10/02/2021 04:12:47PM via free access 70 Gautschy ET AL. to the lack of intercalation, the connection of a date from the Egyptian civil calendar with the heliacal rising of Sothis is vitally important for the reconstruction of chronol- ogy. The new Sothis date from the Old Kingdom (3rd–6th Dynasties) in combination with other astronomical data and radiocarbon dating re-calibrates the chronology of ancient Egypt and consequently the dating of the Pyramids. A chronological model for Dynasties 3 to 6 constructed on the basis of calculated astronomical data and contem- poraneously documented year dates of Pharaohs is presented. Keywords Egyptian Old Kingdom – heliacal rising of Sirius – chronology – lunar dates – regnal year count Introduction The Egyptian civil calendar consisted of 365 days arranged in the three sea- sons Akhet, Peret and Shemu, each containing four months with 30 days and at the end, five additional days (Epagomenals) were added. This civil calendar was probably introduced in the first half of the third millennium BCE, starting with an assumed observation of the heliacal rising of Sirius (Sothis) on the 1st month of Akhet, 1st day. The heliacal rising of Sirius denotes its first visibility in the morning sky after a period of invisibility. Due to the lack of intercalary days, the Egyptian civil calendar permanently shifted one day in four years (tet- raeteris) in comparison to the stars. As a result, the beginning of the year was moving through the civil calendar: By the end of the Old Kingdom the heliacal rising of Sothis had already shifted into the Peret season and during the Second Intermediate Period and the 18th Dynasty of the New Kingdom the New Year occurred in the Shemu season. In Ramesside times (19th Dynasty) the cycle reached the Akhet season again. This phenomenon is known as Sothis-cycle. The mentioning of a heliacal rising of Sothis combined with a date of the Egyptian calendar therefore may allow quite accurate absolute dating using astronom- ical charts.1 Only few Sothic dates are known from ancient Egypt, the oldest complete date so far was the el-Lahun date from the 12th Dynasty.2 Although extremely sparse, these Sothis dates are of highest importance for the chronol- ogy of ancient Egypt and ancient cultures of the Near East since the dating of 1 Krauss, Sothis- und Monddaten; Gautschy, “Sirius.” 2 Krauss, Sothis- und Monddaten; Gautschy, “Sirius”; Luft, Chronologische Fixierung; Borchardt, “Kahun.” Journal of EgyptianDownloaded History from 10 Brill.com10/02/2021 (2017) 69–108 04:12:47PM via free access A New Astronomically Based Chronological Model 71 the Egyptian Middle Kingdom, of the Egyptian New Kingdom, and of neigh- bouring regions depend on them. The New Sothis Date Recently a new Sothis date on an ointment jar was discovered.3 The jar men- tions the “Forthcoming of Sopdet” and the date of a heliacal rising of Sirius on the beaker. For the stylistic dating of our jar several publications were used.4 Such cylindrical beakers contained perfume oil and were often given to people on special occasions and festivals—a tradition still alive in the Coptic church.5 The jar was stylistically dated into the mid to late 5th Dynasty. Inscription, pa- laeography and the astronomical date also point to the Old Kingdom. The in- scription (Fig. 1) starting from the right column is a nominal sentence with pw: gsw n s3-rnp.t 3bd 4 pr.t ḫft pr.t spd.t 3bd 4 3ḫt pw ḫft wp.t -rˁ Ointment made for the protection of the year, month 4, Peret-season, for the forthcoming of Sothis, month 4, Akhet-season it is, made for the first day of the month. The sign “wp.t -rˁ” is a cow’s horn with sun disc and can be translated as “first day of the month” but also as “beginning of the New Year,” most fitting for this festival.6 It mentions the ointment inside the jar, combined with the produc- tion date (4th month, Peret). The reason is the forthcoming of Sothis (Sirius) at the date (4th month, Akhet, 1st day). The Peret date, mentioning the protection of the year may refer to the date of production of the oil: the ointment would have been produced ca. ¾ year in advance of the heliacal rising of Sothis. This is a classic production length for the sacred oils in Egypt.7 Old Kingdom Chronology Historical dating based on information given in king lists, radiocarbon dat- ing, as well as various astronomical dating attempts resulted in different 3 Habicht, et al., “New Sothis Rise.” 4 Aston, Stone Vessels; Günther and Wellauer, Ägyptische Steingefässe. 5 Baligh, “Oil and its importance.” 6 Hannig, Handwörterbuch, 206. 7 Baligh, “Oil and its importance.” Journal of Egyptian History 10 (2017) 69–108 Downloaded from Brill.com10/02/2021 04:12:47PM via free access 72 Gautschy ET AL. Figure 1 Drawing of the ointment jar with the Sothis-inscription in the archaeological collection of the University of Zurich, inv. 5821. Copyright: Michael Habicht, digitally reworked and coloured by Patrick E. Eppenberger. chronologies of the Egyptian Old Kingdom with varying degrees of disagreement.8 All these dating methods share that they are heavily influenced by the fact that 8 See, e.g., Shaw, ed., Oxford History; Krauss, “Lunar Dates,” 429–31; Depuydt, “Sothic Chronology,” 183–84; Dee, “Radiocarbon-based Chronology,” 212–13 and 287; Bárta, “Radiocarbon Dates,” 221; Spence “Orientation of Pyramids.” Journal of EgyptianDownloaded History from 10 Brill.com10/02/2021 (2017) 69–108 04:12:47PM via free access A New Astronomically Based Chronological Model 73 the method of counting years used during Dynasties 3 to 6 is still a matter of debate. The standard theory for many years was that a regular biannual count of regnal years was employed throughout the whole Old Kingdom.9 In the framework of this hypothesis each “year of the xth cattle count” should have been followed by a “year after the xth cattle count.” It has long been noticed that the number of documents containing a “year of the count” and a “year after the count” is not about equal, as one would expect if indeed a biannual year count had been used. Instead—depending on whether graffiti of work- men are included in the statistics or not—the ratio amounts to approximately 2.8:1 and 1.85:1, respectively.10 Disregarding the graffiti results in that a “year after the count” usually occurred approximately every third year, but some- times already every second year. Based on these numbers John Nolan proposed a connection with the original lunar calendar, namely that a “year after the count” was employed if an intercalary month was inserted into the lunar calen- dar at the end of the preceding year in order to keep it in line with the sidereal and solar year.11 Nolan’s hypothesis requires a reduction of the number of reg- nal years usually assigned to Old Kingdom Pharaohs by about 21% and hence a shortening of Old Kingdom chronology. The Lunar Calendar and Intercalary Months Nolan recently proposed that a regular nineteen-year intercalation cycle com- parable to the much later well-known Metonic cycle has been used in third millennium ancient Egypt.12 Although the regular Metonic intercalation cycle may well have been known prior to its first unambiguously documented attes- tation one may doubt that such a cycle was used 2000 years earlier. However, this does no harm to Nolan’s basic hypothesis because the application of a regular intercalation cycle would by no means be a prerequisite for the func- tioning of the whole system. The so-called original lunar calendar was tied to the heliacal rising of the star Sirius.13 This event refers to the first visibil- ity of the star Sirius in the morning sky shortly before sunrise after a period of invisibility in the night sky. A new lunar month began with the invisibility of the lunar crescent in the morning sky. A normal year consisted of twelve lunar 9 Gardiner, “Regnal Years.” 10 Nolan, “Cattle Counts,” 79. 11 Nolan, “Cattle Counts,” 92. 12 Nolan, “Phyle Rotations,” 340–44. 13 Parker, Calendars, 30–50. Journal of Egyptian History 10 (2017) 69–108 Downloaded from Brill.com10/02/2021 04:12:47PM via free access 74 Gautschy ET AL. months. Since such a lunar year with twelve months is about ten days shorter than a sidereal year an extra month has to be inserted after three years, and at times already after two years, in order to keep the lunar calendar synchronized with the sidereal year.14 The decisive astronomical phenomenon for the inser- tion of an additional lunar month was the heliacal rising of the star Sirius.