Pharaonic Egypt's calendrical system was both straightforward and simple. From the first dynasty onward, the Egyptian year was divided into three seasons, based on the agricultural rhythm of the Nile Valley: (1) ʒḫt, inundation; (2) prt, emergence (of crops); and (3) šmw, harvest. These seasons consisted of four months apiece, each containing thirty days. Hence, the basic year of the Egyptians comprised a regular number of days (360) as well as an orderly number of months (12). Such a system had to have five additional days added to it, the epagomenals (“days above the year”), which neatly fixed the annual rotation of the sun to a set integer of 365; there were no intercalary days in that native year.

The calendrical order was most advantageous to Egyptologists' cumulative reckoning of such large-scale time elements as dynasties and epochs. Mainly from hypothetical reasoning, it is assumed that the Nile year was created by the early Egyptian state in order to regularize its economic stability (tax collecting through a census placed on cattle) as well as to record its kings' reigns. Modern scholars, therefore, call this 365-day year the civil calendar, to indicate the original purpose of its reckoning. The number of months, as well as their names, were based on an older, lunar calendar. In this earlier system, it is unclear whether the Egyptians intercalated an extra month (the thirteenth), every three years or so, to bring the calendar into accord with the seasons. Although the extant data neither support nor reject that, traces of the lunar calendar exist in the presence of some feast days, which were determined by the moon's cycle rather than permanently fixed on a day (or days) within the civil calendar.

Some ancient Egyptian festivals were therefore determined by the moon, and quite a number of significant religious events were solely set to a specific lunar day, such as the new moon. For example, the Valley Feast took place within the tenth Egyptian civil month but was not permanently set on a predetermined day within that month. Similarly, the funerary event of Wagy seems to have taken place on day eighteen of lunar month two, although a civil calendar counterpart always occurred on day eighteen of the first civil month. For the most part, Egyptian religious festivals became civil calendar–based since a change had been made from lunar time to the civil calendar when it came into being.

The regnal years of the kings were also reorganized so that they coincided with civil calendar years. In Predynastic times, a lunar calendar must have been the basis for the regnal year. In the Old Kingdom, as the Palermo Stone clearly indicates, the regnal year counts were originally labeled by names of auspicious or important events that occurred within a civil calendar year of 365 days, among which one can single out building projects of a religious nature. After the second dynasty, the regnal years also became orderly, since they were referred to, on a regular basis, by the biennial cattle census that took place throughout Egypt. Eventually, probably by the sixth dynasty, the biennial census was replaced by an annual one. From that time on, all regnal years were rationalized so that the king's year in office was nothing more than an integer that was counted every civil calendar year. The causes for such change included the importance of the centralized state apparatus and the necessity to establish a workable and relatively easy method of counting. Egyptian regnal years were dependent upon a 365-day civil calendar year, not a lunar year, and they operated independently of whether the anniversary of a pharaoh's accession caused a change in the year count (as in the New Kingdom) or whether the presence of subsequent new year's days effected such a change. In the Middle Kingdom (unlike the New Kingdom), counting of regnal years was reckoned from the first day of the civil calendar year to the next, excluding the opening year, which almost always began within a civil calendar year.

Although later sources, mainly of Greco-Roman times, put great emphasis on the star the Egyptians called Sothis (our Sirius), as being connected with an enormous cycle of 1,460 Egyptian civil years, that lengthy period seems not to have been employed by them for any historical reckoning. Nonetheless, the commencement of a year was intimately associated with the goddess Sothis (identified with the goddess Isis), especially if an ideal, rather than a real, beginning was to be stressed. Such was the case because the reappearance of the star Sothis at dawn, after a disappearance of seventy days (its heliacal rising, prt spdt), was originally linked with the inauguration of the year at a time when the Nile waters had crested. Owing to this connection, scholars argue that the first day of the just-created civil year (new year's day) began at the exact time of prt spdt. In many extant festival calendars, as well as a few other sources, Sothis' heliacal rising was given great prominence although it did not interrupt the mundane flow of time, since the astronomical event occurred independently of the way the civil calendar operated.

Research has obviated the need to claim that the Egyptians invented a second lunar calendar, somewhat later than their civil calendar. From our knowledge of the festival system, it appears that most religious celebrations were only on the civil calendar. Those festivals that were lunar-based seem to have been organized around specific lunar occurrences (such as the new moon) that could be seen with the naked eye, but they were nevertheless based partly on the civil calendar. It was understood that the lunar occurrence was fixed within a given civil month and that no independent lunar year was operating alongside the established civil calendar. Therefore, all administrative work, such as daily accounts and the like, were set by the civil calendar; lunar-based events appear to have been restricted solely to the cultic sphere.

The names of the twelve civil months betray their origins, since it is evident that they are mere copies of the original names of their twelve lunar-month counterparts. The first, Thoth, was named after the god of the moon, who was also the reckoner of time. The third, Athyr, overtly indicates that it was named after the goddess Hathor, whose festival took place on day one of the following civil month. Khoiak, the designation for civil month four, was similarly borrowed from a major religious event that occurred at the crucial change of season—from the first season, ʒḫt, to the second, prt—the festival held on day one of the fifth month. In this case, the first day of peret served as a second new year's day, on which the rejuvenation of the subsistence-based agricultural society of Predynastic Egypt was predicated. A similar change from the second season to the third can be observed with the name of month eight, Renenutet. Then, the goddess of the harvest Renenutet bequeathed her name to the final civil month, šmw, in recognition of the festival for the gathering of grain, which took place at the beginning of the ninth month. In some cases, for historical reasons, the designations of the civil months were changed. For example, Menchet (“clothing”), civil month number two, was altered to Paophi in honor of the important Theban festival of Opet, which occurred at that time. In similar fashion, Phamenoth, civil month seven, reflected the festival of the deified Amenhotpe I. Yet the final civil month revealed its origins in the rebirth of the sun god Re, for that is what its name, Mesore, actually meant. Earlier, the designation was Wep-renpet (“the opener of the year”), called after the most important festival in the year, that of new year's day, on the first day of Thoth, the first month.

A careful comparison of the month names has determined that at least some of the older designations were based on key religious festivals; however, they seem always to have occurred on or about day one of the following civil month. The clear case of Athyr, mentioned above, provides an excellent example of this. Although the civil month was the third in the year, its religious counterpart, the feast of Hathor, began with the following civil month. Insofar as the civil months postdate the original lunar calendar months in which the key feasts were first celebrated, any attempt to equate a month name with the eponymous feast name must consider this. Even at the inception of the newly created civil calendar, such a shunting of festival dates must have occurred—an alteration partially explained by the original lunar year of only 354 days, and the new civil year of 365 days. The difference of nineteen days (called the lunar-solar epact) explains the lack of equivalence and provides a reason for the observance of the festival of the moon god Thoth on day nineteen of the first civil month. (In a similar lack of concurrence, present-day Easter and Passover continue to be celebrated on old lunar dates that have no fixed Western calendar dates.)

The various festival calendars of the Egyptians reflected the civil calendar insofar as they located their celebrations within the civil year. Quite often a clear separation was made between the “festivals of heaven,” which occurred more than once a year, and the “seasonal festivals,” which took place annually. By the nineteenth dynasty, the first group merely comprised the various celebrations in honor of lunar days (e.g., day 1, 2, 6, 15, and the like). In contrast, the second group reflected the developed theological outlook of the various temples, wherein the crucial religious manifestations took place once a year. Note that the dichotomy was not merely one of celestial phenomena versus earthly ones, since the heliacal rising of Sothis was placed under the “seasonal festivals.” The festival calendars are very important to us because they reveal, in precise fashion, just which days were of crucial importance to the Egyptians and how they were celebrated.

Other segments of time from ancient Egypt also are known. A week was in reality ten days, with the standard holidays at the end (day ten) and the day following. Hour measurements were known, too, but they were of irregular length, roughly identical to the “seasonal hours” of Hellenistic and Roman times. There are Egyptian words for small segments of time other than the hour, but no precise designations for the “half-hour,” the “quarter hour,” or the “minute.” Such a lack of specificity was mainly the result of the relatively simple timekeeping used in the Nile Valley; pharaonic civilization had no need for precise time intervals such as seconds or minutes. The Egyptian hours appear to have been based always on groupings of stars. In the First Intermediate Period, if not earlier, a system of decanal stars was invented, by which there were twelve night hours. These twelve intervals were determined by sight, and they depended on the sighting of various star groups that cannot be identified. As each star group rose, it designated a specific hour of the night sky for ten days (hence each is called a “decan” and the method a decanal system). The decan-hour stars would then move on one integer, for 120 days, or 12 “weeks.” At first, the system depended on naked-eye viewing at the eastern horizon; later, in the Middle Kingdom, a more refined method of observation was used, in which the crossing of the star groups across a meridian determined the nightly hours. From the New Kingdom onward, the Egyptians preferred to work out nocturnal timekeeping by the transit of stars across various reference points on a man's body (head, neck, etc.) as he faced south and was checked by a second man who faced him. All such attempts to work out an effective hour system for the night were affected by various difficulties.

Research on such star clocks has confirmed their usefulness; nevertheless, by modern standards such time-keeping was limited by the lack of a coordinate system for the heavens. Only during the Ptolemaic dynasty was a zodiacal system introduced to Egypt, one that had as its basis the division of the Sun's annual path along the ecliptic. This system was based on a “degree” system—originally of Babylonian origin—into which each star group occupied thirty “degrees,” there being twelve star groups in all (30 × 12 = 360 degrees, as used today, to describe a complete circle).

The beginning of the Egyptian day was at “dawn,” probably in morning twilight (although that is contested by some researchers); the actual dawn, when the Sun first rises in the east, is also a possibility. The inscriptional material is ambiguous. The crucial point is that the Egyptians' calendrical perspective was fixed toward morning sightings directed at the eastern horizon. A lunar month began on the day when the waning crescent moon could not be sighted on the eastern horizon. (The Egyptian month was therefore regulated in a different tradition than either the Babylonian or the Greek, in which months were based on the evening sighting of the first lunar crescent in west). Since the absence of any lunar crescent indicates that the Egyptian system depended on the eastern, morning sighting, the Egyptian lunar epoch occurred about one day earlier than those cultures that regarded the day as commencing with the first western, evening sighting.

The Old Egyptian names for the lunar days are useful to survey for a linguistic connection. The first day, that of no lunar crescent visibility, was connected to the Egyptian word for “new,” whereas the “crescent” gave its name to the second day, and the third day was called “arrival,” indicating actual visibility (the first crescent might be delayed by atmospheric anomalies, so that it would turn up on day three). There was a “second arrival” on day sixteen, heralding the completion of the full moon (from day fifteen, the Egyptian “half month”), with “first quarter” and “last quarter” (called “parts”) the terms for day seven and day twenty-three, respectively. Finally, day thirty was associated with the god Min, owing to his virility; in this case, it is clear that the association with Min indicated procreation. Theologically, the following day was considered the “moon in the womb,” with its appearance—birth—occurring on day two of the following lunar month.

For the Ptolemaic period, a few extant sources from Egypt indicate that a regular correlation was drawn between lunar months and their civil calendar counterparts. Papyrus Carlsberg 9, in particular, supplies us with a full (though not complete) listing of such equivalences; from the text, a relatively simple, albeit artificial, cycle was introduced to Egypt, in which 25 Egyptian years (of 365 days apiece) were equated with 309 lunar months, the latter consisting of 16 years of 12 months and 9 of 13 months (365 × 25 = 9,125 days; 309 lunar months with those parameters yield 9,124.95 days). Such a cycle eliminates the need for an actual lunar sighting. Originally thought to be a native Egyptian creation, reinterpretations have placed its sophisticated workings outside the Nile Valley. Other scholarly arguments have connected this Demotic papyrus with the Macedonian calendar—in use for the duration of the Greek domination over Egypt—although serious questions remain concerning the exact extent of its use. One difficulty in textual interpretation is that the columns of odd lunar-civil calendar equivalences were not presented, if those sections merely repeated the integers in the even columns, as some believe, then the entries in Papyrus Carlsberg 9 are still incomplete. Some Egyptologists see the inauguration of this cycle (c.357 BCE) being based on the nonvisibility of the lunar crescent. Classicists interested in Ptolemaic Egypt prefer to understand the system as one developed for equating Egyptian days and months with the Macedonian calendar, and one extremely fragmentary Greek papyrus reveals that such an equivalence was made (Papyrus Rylands 586); however, the extant pieces are not sufficient to draw any firm conclusions regarding its origins.



  • Altenmüller, Hartwig. “Feste.” In Lexikon der Ägyptologie, 1: 172–191. Wiesbaden, 1975. Very detailed study of all Egyptian festival calendars and their connection to the various religious celebrations of the Egyptians.
  • Clagett, Marshall. Ancient Egyptian Science, vol. 2: Calendars, Clocks and Astronomy. Philadelphia, 1995. A useful, though surprisingly incomplete and already dated study by a very competant non-Egyptologist.
  • Gardiner, Alan. “The Problem of the Month Names.” Revue de l'égyptologie 10 (1955), 9–31. Discusses problems of Richard Parker's analyses regarding Egyptian civil months.
  • Gryzbek, Erhard. Du calendrier macédonian au calendrier ptolémaique: Basel, 1990. Problemes de chronologie hellenistique. Schweizensche Bieträg zur Altertumswissenschaft, 20. Basel, 1990. A refreshing look at the Macedonian-Egyptian calendar, although somewhat limited by the author's presuppositions.
  • Ingham, M. F. “The Length of the Sothic Cycle.” Journal of Egyptian Archaeology 55 (1969), 36–40. A useful study of the time it takes the star Sothis (Sirius) to return to its exact spot in the sky.
  • Koenen, Ludwig. Eine agonistische Inschrift aus Ägypten und frühptolemäische Königsfeste. Beiträge zur klassichen Philolologie, 56. Meisenheim am Glan, 1977. An attempt to revise Alan Samuel's Macedonian-Egyptian calendars; also based on Papyrus Carlsberg 9.
  • Krauss, Rolf. Sothis-und Monddaten: Studien zur astronomischen und technichischen Chronologie Altägyptens. Hildesheimer ägyptologische Beiträg, 20. Hildelsheim, 1985. The first major attempt to present Egyptian calendrics and chronology from a mature point of view since Richard Parker's works.
  • Leitz, Christian. Studien zur ägyptischen Astronomie. Ägyptologische Abhandlungen, 49. Wiesbaden, 1989. An idiosyncratic study on Egyptian calendrics and astronomy that tends to claim modern scientific exactitude for the ancient Egyptians.
  • Leitz, Christian. Altägyptische Sternuhren. Orientalia Lovaniensia analecta, 62. Leuven, 1995. A controversial study of the Egyptian decanal star system that attempts to identify various star groups (“constellations”) of the Egyptians.
  • Luft, Ulrich. Die chronologische Fixierung des ägyptischen Mittleren Reiches nach dem Tempelarchiv von Illahun. Sitzungsberichte der Österreichischen Akademie der Wissenschaften, 598. Vienna, 1992. An up-to-date analysis of the Middle Kingdom temple archive from Illahun and its importance for festival dating.
  • Neugebauer, Otto, and Richard A. Parker. Egyptian Astronomical Texts. 3 vols. Brown Egyptological Studies, 3. London and Providence, 1960–1969. The basic compendium on Egyptian astronomy by two great scholars in the field.
  • Parker, Richard A. The Calendars of Ancient Egypt. Studies in Ancient Oriental Civilization, 26. Chicago, 1950. The seminal study, though now dated, on Egyptian calendrics by the major English-speaking scholar in the field.
  • Parker, Richard A. “The Problem of the Month Names: A Reply.” Revue de l'égyptologie 11 (1957), 85–101. A relatively successful rebuttal of Alan Gardiner's attempt to jettison the 1950 study.
  • Samuel, Alan Edouard. Ptolemaic Chronology. Munchener Beiträge zur Papyrusforschung und antiken Rechtsgeschichte, 43. Munich, 1962. Originally a revolutionary work concerned with the Macedonian calendar in Egypt; Samuel was the first classicist to employ the Demotic evidence from Papyrus Carlsberg 9 to resolve the problem.
  • Schott, Siegfried. Altägyptische Festdaten. Wiesbaden, 1950. A useful compendium of Egyptian festivals (mainly Theban) with a lengthy introduction concerning ancient Egyptian timekeeping and calendrics.
  • Spalinger, Anthony J. Three Studies on Egyptian Feasts and their Chronological Implications. Baltimore, 1992. A new Egyptian festival calendar and the various calendrical results that its study reveals.
  • Spalinger, Anthony J., ed. Revolutions in Time: Studies in Ancient Egyptian Calendrics. San Antonio, 1994. A collection of four studies concerned with the interrelated aspects of dating, various time epochs, festivals, and the lunar-civil calendar interrelationship.

Anthony J. Spalinger