The ancient Egyptian calendar – a civil calendar – was a solar calendar with a 365-day year. The year consisted of three seasons of 120 days each, plus an intercalary month of five epagomenal days treated as outside of the year proper. Each season was divided into four months of 30 days. These twelve months were initially numbered within each season but came to also be known by the names of their principal festivals. Each month was divided into three 10-day periods known as decans or decades. It has been suggested that during the Nineteenth Dynasty and the Twentieth Dynasty the last two days of each decan were usually treated as a kind of weekend for the royal craftsmen, with royal artisans free from work.
Because this calendrical year was nearly a quarter of a day shorter than the solar year, the Egyptian calendar lost about one day every four years relative to the Gregorian calendar. It is therefore sometimes referred to as the wandering year (Latin : annus vagus), as its months rotated about one day through the solar year every four years. Ptolemy III 's Canopus Decree attempted to correct this through the introduction of a sixth epagomenal day every four years but the proposal was resisted by the Egyptian priests and people and abandoned until the establishment of the Alexandrian or Coptic calendar by Augustus. The introduction of a leap day to the Egyptian calendar made it equivalent to the reformed Julian calendar, although by extension it continues to diverge from the Gregorian calendar at the turn of most centuries.
This civil calendar ran concurrently with an Egyptian lunar calendar which was used for some religious rituals and festivals. Some Egyptologists have described it as lunisolar, with an intercalary month supposedly added every two or three years to maintain its consistency with the solar year, but no evidence of such intercalation before the 4th century BC has yet been discovered.
Current understanding of the earliest development of the Egyptian calendar remains speculative. A tablet from the reign of the First Dynasty pharaoh Djer (c. 3000 BC) was once thought to indicate that the Egyptians had already established a link between the heliacal rising of Sirius (Ancient Egyptian : Spdt or Sopdet, "Triangle"; Greek : Σῶθις , Sôthis) and the beginning of their year, but more recent analysis has questioned whether the tablet's picture refers to Sirius at all. Similarly, based on the Palermo Stone, Alexander Scharff proposed that the Old Kingdom observed a 320-day year, but his theory has not been widely accepted. Some evidence suggests the early civil calendar had 360 days, although it might merely reflect the unusual status of the five epagomenal days as days "added on" to the proper year.
With its interior effectively rainless for thousands of years,ancient Egypt was "a gift of the river" Nile, whose annual flooding organized the natural year into three broad natural seasons known to the Egyptians as:
As early as the reign of Djer (c. 3000 BC, Dynasty I), yearly records were being kept of the flood's high-water mark. Otto E. Neugebauer noted that a 365-day year can be established by averaging a few decades of accurate observations of the Nile flood without any need for astronomical observations, although the great irregularity of the flood from year to year and the difficulty of maintaining a sufficiently accurate Nilometer and record in prehistoric Egypt has caused other scholars to doubt that it formed the basis for the Egyptian calendar.
Note that the names of the three natural seasons were incorporated into the Civil calendar year (see below), but as this calendar year is a wandering year, the seasons of this calendar slowly rotate through the natural solar year, meaning that Civil season Akhet/Inundation only occasionally coincided with the Nile inundation.
The Egyptians appear to have used a purely lunar calendar prior to the establishment of the solar civil calendar 4th century BCE, there is no sure way to reconstruct exact dates in the lunar calendar from its known dates. The difference between beginning the day at the first light of dawn or at sunrise accounts for an 11–14 year shift in dated observations of the lunar cycle. It remains unknown how the Egyptians dealt with obscurement by clouds when they occurred and the best current algorithms have been shown to differ from actual observation of the waning crescent moon in about one-in-five cases.in which each month began on the morning when the waning crescent moon could no longer be seen. Until the closing of Egypt's polytheist temples under the Byzantines, the lunar calendar continued to be used as the liturgical year of various cults. The lunar calendar divided the month into four weeks, reflecting each quarter of the lunar phases. Because the exact time of morning considered to begin the Egyptian day remains uncertain and there is no evidence that any method other than observation was used to determine the beginnings of the lunar months prior to the
Parker and others have argued for its development into an observational and then calculated lunisolar calendar day intercalary month every two to three years to accommodate the lunar year's loss of about 11 days a year relative to the solar year and to maintain the placement of the heliacal rising of Sirius within its twelfth month. No evidence for such a month, however, exists in the present historical record.which used a 30
Ꜣbd n ḥwt-nṯr
A second lunar calendar is attested by a demotic astronomical papyrus CE which outlines a lunisolar calendar operating in accordance with the Egyptian civil calendar according to a 25 year cycle. The calendar seems to show its month beginning with the first visibility of the waxing crescent moon, but Parker displayed an error in the cycle of about a day in 500 years, using it to show the cycle was developed to correspond with the new moon around 357 BCE. This date places it prior to the Ptolemaic period and within the native Egyptian Dynasty XXX. Egypt's 1st Persian occupation, however, seems likely to have been its inspiration. This lunisolar calendar's calculations apparently continued to be used without correction into the Roman period, even when they no longer precisely matched the observable lunar phases.dating to sometime after 144
The days of the lunar month — known to the Egyptians as a "temple month"— were individually named and celebrated as stages in the life of the moon god, variously Thoth in the Middle Kingdom or Khonsu in the Ptolemaic era: "He ... is conceived ... on Psḏntyw; he is born on Ꜣbd; he grows old after Smdt".
|Egyptian||Meaning (if known)|
|1||Psḏtyw||Literal meaning unknown but possibly related to the Ennead; the day of the New Moon.|
|"Beginning the Month" or "The Month"; the beginning of the Crescent Moon.|
|4||Prt Sm||"The Going Forth of the Sm", a kind of priest|
|5||I͗ḫt Ḥr Ḫꜣwt||"Offerings upon the Altar"|
|7||Dnı͗t||"Partial"; the first-quarter day.|
|12||Unknown||"Partial" the second-quarter day.|
|Literal meaning uncertain; the day of the Full Moon.|
|16||Mspr Sn Nw|
"Covering the Head"
|17||Sı͗ꜣw||Second Quarter Day|
|18||I͗ꜥḥ||"Day of the Moon"|
|23||Dnı͗t||"Partial"; the third-quarter day.|
|26||Prt||"The Going Forth"|
|28||Ḥb Sd Nwt||"The Jubilee of Nut"|
|30||Prt Mn||"The Going Forth of Min"|
The civil calendar was established at some early date in or before the Old Kingdom, with probable evidence of its use early in the reign of Shepseskaf (c. 2510 BC, Dynasty IV) and certain attestation during the reign of Neferirkare (mid-25th century BC, Dynasty V). It was probably based upon astronomical observations of Sirius whose reappearance in the sky closely corresponded to the average onset of the Nile flood through the 5th and 4th millennium BC. A recent development is the discovery that the 30-day month of the Mesopotamian calendar dates as late as the Jemdet Nasr Period (late 4th-millennium BC), a time Egyptian culture was borrowing various objects and cultural features from the Fertile Crescent, leaving open the possibility that the main features of the calendar were borrowed in one direction or the other as well.
The civil year comprised exactly 365 days, I Akhet 1.divided into 12 months of 30 days each and an intercalary month of five days, were celebrated as the birthdays of the gods Osiris, Horus, Set, Isis, and Nephthys. The regular months were grouped into Egypt's three seasons, which gave them their original names, and divided into three 10-day periods known as decans or decades. In later sources, these were distinguished as "first", "middle", and "last". It has been suggested that during the Nineteenth Dynasty and the Twentieth Dynasty the last two days of each decan were usually treated as a kind of weekend for the royal craftsmen, with royal artisans free from work. Dates were typically expressed in a YMD format, with a pharaoh's regnal year followed by the month followed by the day of the month. For example, the New Year occurred on
|Lord of Years|
The importance of the calendar to Egyptian religion is reflected in the use of the title "Lord of Years" (Nb Rnpt)for its various creator gods. Time was also considered an integral aspect of Maat, the cosmic order which opposed chaos, lies, and violence.
The civil calendar was apparently established in a year when Sirius rose on its New Year (I Akhet 1) but, because of its lack of leap years, it began to slowly cycle backwards through the solar year. Sirius itself, about 40° below the ecliptic, follows a Sothic year almost exactly matching that of the Sun, with its reappearance now occurring at the latitude of Cairo (ancient Heliopolis and Memphis) on 19 July (Julian), only two or three days later than its occurrence in early antiquity.
Following Censorinus (I Akhet 2); four years later, it would have reappeared on the day after that; and so on through the entire calendar until its rise finally returned to I Akhet 1 1460 years after the calendar's inception, an event known as "apocatastasis". Owing to the event's extreme regularity, Egyptian recordings of the calendrical date of the rise of Sirius have been used by Egyptologists to fix its calendar and other events dated to it, at least to the level of the four-Egyptian-year periods which share the same date for Sirius's return, known as "tetraëterides" or "quadrennia". For example, an account that Sothis rose on III Peret 1—the 181st day of the year—should show that somewhere 720, 721, 722, or 723 years have passed since the last apocatastasis. Following such a scheme, the record of Sirius rising on II Shemu 1 in 239 BC implies apocatastases on 1319 and 2779 BC ±3 years. Censorinus's placement of an apocatastasis on 21 July AD 139 permitted the calculation of its predecessors to 1322, 2782, and 4242 BC. [ failed verification ] The last is sometimes described as "the first exactly dated year in history" but, since the calendar is attested before Dynasty XVIII and the last date is now known to far predate early Egyptian civilization, it is typically credited to Dynasty II around the middle date.and Meyer, the standard understanding was that, four years from the calendar's inception, Sirius would have no longer reappeared on the Egyptian New Year but on the next day
|3500 BC||III Peret 3||July 16||June 18|
|3000 BC||III Shemu 8||July 16||June 22|
|2500 BC||III Akhet 8||July 16||June 26|
|2000 BC||III Peret 14||July 17||June 30|
|1500 BC||III Shemu 19||July 17||July 4|
|1000 BC||III Akhet 19||July 17||July 8|
|500 BC||III Peret 25||July 18||July 13|
|AD 1||III Shemu 30||July 18||July 16|
|AD 500||IV Akhet 2||July 20||July 22|
The classic understanding of the Sothic cycle relies, however, on several potentially erroneous assumptions. Following Scaliger, July but ancient authorities give a variety of 'fixed' dates for the rise of Sirius. His use of the year 139 seems questionable, as 136 seems to have been the start of the tetraëteris and the later date chosen to flatter the birthday of Censorinus's patron. Perfect observation of Sirius's actual behavior during the cycle—including its minor shift relative to the solar year—would produce a period of 1457 years; observational difficulties produce a further margin of error of about two decades. Although it is certain the Egyptian day began in the morning, another four years are shifted depending on whether the precise start occurred at the first light of dawn or at sunrise. It has been noted that there is no recognition in surviving records that Sirius's minor irregularities sometimes produce a triëteris or penteteris (three- or five-year periods of agreement with an Egyptian date) rather than the usual four-year periods and, given that the expected discrepancy is no more than 8 years in 1460, the cycle may have been applied schematically according to the civil years by Egyptians and the Julian year by the Greeks and Romans. The occurrence of the apocatastasis in the 2nd millennium BC so close to the great political and sun-based religious reforms of Amenhotep IV /Akhenaton also leaves open the possibility that the cycle's strict application was occasionally subject to political interference. The record and celebration of Sirius's rising would also vary by several days (equating to decades of the cycle) in eras when the official site of observation was moved from near Cairo. The return of Sirius to the night sky varies by about a day per degree of latitude, causing it to be seen 8–10 days earlier at Aswan than at Alexandria, a difference which causes Rolf Krauss to propose dating much of Egyptian history decades later than the present consensus.Censorinus's date is usually emended to 20
Following Alexander the Great's conquest of the Persian Empire, the Macedonian Ptolemaic Dynasty came to power in Egypt, continuing to use its native calendars with Hellenized names. In 238 BC, Ptolemy III's Canopus Decree ordered that every 4th year should incorporate a sixth day in its intercalary month, honoring him and his wife as gods equivalent to the children of Nut. The reform was resisted by the Egyptian priests and people and was abandoned.
Egyptian scholars were involved with the establishment of Julius Caesar's reform of the Roman calendar, although the Roman priests initially misapplied its formula and—by counting inclusively—added leap days every three years instead of every four. The mistake was corrected by Augustus through omitting leap years for a number of cycles until AD 4. As the personal ruler of Egypt, he also imposed a reform of its calendar in 26 or 25 BC, possibly to correspond with the beginning of a new Callipic cycle, with the first leap day occurring on 6 Epag. in the year 22 BC. This "Alexandrian calendar" corresponds almost exactly to the Julian, causing 1 Thoth to remain at 29 August except during the year before a Julian leap year, when it occurs on 30 August instead. The calendars then resume their correspondence after 4 Phamenoth / 29 February of the next year.
For much of Egyptian history, the months were not referred to by individual names, but were rather numbered within the three seasons.As early as the Middle Kingdom, however, each month had its own name. These finally evolved into the New Kingdom months, which in turn gave rise to the Hellenized names that were used for chronology by Ptolemy in his Almagest and by others. Copernicus constructed his tables for the motion of the planets based on the Egyptian year because of its mathematical regularity. A convention of modern Egyptologists is to number the months consecutively using Roman numerals.
A persistent problem of Egyptology has been that the festivals which give their names to the months occur in the next month. Alan Gardiner proposed that an original calendar governed by the priests of Ra was supplanted by an improvement developed by the partisans of Thoth. Parker connected the discrepancy to his theories concerning the lunar calendar. Sethe, Weill, and Clagett proposed that the names expressed the idea that each month culminated in the festival beginning the next.
|Seasonal||Middle Kingdom||New Kingdom|
|I||I Akhet |
|1st Month of Flood|
|II||II Akhet |
|2nd Month of Flood|
|III||III Akhet |
|3rd Month of Flood|
|IV||IV Akhet |
|4th Month of Flood|
|V||I Peret |
|1st Month of Growth|
|VI||II Peret |
|2nd Month of Growth|
|VII||III Peret |
|3rd Month of Growth|
|Rḫ Nds||PꜢ n-imn-ḥtp.w||Φαμενώθ||Phamenṓth||Ⲡⲁⲣⲉⲙϩⲁⲧ||Baramhat|
|VIII||IV Peret |
|4th Month of Growth|
|IX||I Shemu |
|1st Month of Low Water|
|X||II Shemu |
|2nd Month of Low Water|
|XI||III Shemu |
|3rd Month of Low Water|
|XII||IV Shemu |
|4th Month of Low Water|
|Opening of the Year|
|Birth of the Sun |
|—|| Intercalary Month |
|—||Those upon the Year|
|ἐπαγόμεναι||epagómenai||Ⲡⲓⲕⲟⲩϫⲓ ⲛ̀ⲁⲃⲟⲧ||Bikudji en abod|
The reformed Egyptian calendar continues to be used in Egypt as the Coptic calendar of the Egyptian Church and by the Egyptian populace at large, particularly the fellah, to calculate the agricultural seasons. It differs only in its era, which is dated from the ascension of the Roman emperor Diocletian. Contemporary Egyptian farmers, like their ancient predecessors, divide the year into three seasons: winter, summer, and inundation. It is also associated with local festivals such as the annual Flooding of the Nile and the ancient Spring festival Sham el-Nessim .
The Ethiopian calendar is based on this reformed calendar but uses Amharic names for its months and uses a different era. The French Republican Calendar was similar, but began its year at the autumnal equinox. British orrery maker John Gleave represented the Egyptian calendar in a reconstruction of the Antikythera mechanism.
A calendar is a system of organizing days. This is done by giving names to periods of time, typically days, weeks, months and years. A date is the designation of a single, specific day within such a system. A calendar is also a physical record of such a system. A calendar can also mean a list of planned events, such as a court calendar or a partly or fully chronological list of documents, such as a calendar of wills.
An hour is a unit of time conventionally reckoned as 1⁄24 of a day and scientifically reckoned as 3,599–3,601 seconds, depending on conditions. There are 60 minutes in an hour, and 24 hours in a day.
Intercalation or embolism in timekeeping is the insertion of a leap day, week, or month into some calendar years to make the calendar follow the seasons or moon phases. Lunisolar calendars may require intercalations of both days and months.
The Julian calendar, proposed by Julius Caesar in AUC 708, was a reform of the Roman calendar. It took effect on 1 January AUC 709 , by edict. It was designed with the aid of Greek mathematicians and astronomers such as Sosigenes of Alexandria.
A lunar calendar is a calendar based on the monthly cycles of the Moon's phases, in contrast to solar calendars, whose annual cycles are based only directly on the solar year. The most commonly used calendar, the Gregorian calendar, is a solar calendar system that originally evolved out of a lunar calendar system. A purely lunar calendar is also distinguished from a lunisolar calendar, whose lunar months are brought into alignment with the solar year through some process of intercalation. The details of when months begin varies from calendar to calendar, with some using new, full, or crescent moons and others employing detailed calculations.
The Roman calendar was the calendar used by the Roman kingdom and republic. The term often includes the Julian calendar established by the reforms of the dictator Julius Caesar and emperor Augustus in the late 1st century BC and sometimes includes any system dated by inclusive counting towards months' kalends, nones, and ides in the Roman manner. The term usually excludes the Alexandrian calendar of Roman Egypt, which continued the unique months of that land's former calendar; the Byzantine calendar of the later Roman Empire, which usually dated the Roman months in the simple count of the ancient Greek calendars; and the Gregorian calendar, which refined the Julian system to bring it into still closer alignment with the tropical year.
Sopdet is the ancient Egyptian name of the star Sirius and its personification as an Egyptian goddess. Known to the Greeks as Sothis, she was conflated with Isis as a goddess and Anubis as a god.
The Iranian calendars or Iranian chronology are a succession of calendars invented or used for over two millennia in Iran, also known as Persia. One of the longest chronological records in human history, the Iranian calendar has been modified time and again during its history to suit administrative, climatic, and religious purposes. The most influential face in laying the frameworks for the calendar and its precision was the 11 century Persian polymath, hakim Omar Khayyam.
The Season of the Inundation or Flood was the first season of the lunar and civil Egyptian calendars. It fell after the intercalary month of Days over the Year and before the Season of the Emergence.
The Season of the Emergence was the second season of the lunar and civil Egyptian calendars. It fell after the Season of the Inundation and before the Season of the Harvest.
The Season of the Harvest or Low Water was the third and final season of the lunar and civil Egyptian calendars. It fell after the Season of the Emergence and before the spiritually dangerous intercalary month, after which the New Year's festivities began the Season of the Inundation (Ꜣḫt).
The heliacal rising or star rise of a star occurs annually, or the similar phenomenon of a planet, when it first becomes visible above the eastern horizon at dawn just before sunrise, after it has spent a season behind the sun rendering it invisible. Historically, the most important such rising is that of Sirius, which was an important feature of the Egyptian calendar and astronomical development. The rising of the Pleiades heralded the start of the Ancient Greek sailing season, using celestial navigation.
The Babylonian calendar was a lunisolar calendar with years consisting of 12 lunar months, each beginning when a new crescent moon was first sighted low on the western horizon at sunset, plus an intercalary month inserted as needed by decree. The calendar is based on a Sumerian predecessor preserved in the Umma calendar of Shulgi.
The Sothic cycle or Canicular period is a period of 1,461 Egyptian civil years of 365 days each or 1,460 Julian years averaging 365¼ days each. During a Sothic cycle, the 365 day year loses enough time that the start of its year once again coincides with the heliacal rising of the star Sirius on 19 July in the Julian calendar. It is an important aspect of Egyptology, particularly with regard to reconstructions of the Egyptian calendar and its history. Astronomical records of this displacement may have been responsible for the later establishment of the more accurate Julian and Alexandrian calendars.
Mesori is the twelfth month of the ancient Egyptian and Coptic calendars. It is identical to Nahase in the Ethiopian calendar.
The intercalary month or epagomenal days of the ancient Egyptian, Coptic, and Ethiopian calendars are a period of five days in common years and six days in leap years in addition to those calendars' 12 standard months, sometimes reckoned as their thirteenth month. They originated as a periodic measure to ensure that the heliacal rising of Sirius would occur in the 12th month of the Egyptian lunar calendar but became a regular feature of the civil calendar and its descendants. Coptic and Ethiopian leap days occur in the year preceding Julian and Gregorian leap years.
The ancient Egyptian units of measurement are those used by the dynasties of ancient Egypt prior to its incorporation in the Roman Empire and general adoption of Roman, Greek, and Byzantine units of measurement. The units of length seem to have originally been anthropic, based on various parts of the human body, although these were standardized using cubit rods, strands of rope, and official measures maintained at some temples.
The Decree of Canopus is a trilingual inscription in three scripts, which dates from the Ptolemaic period of ancient Egypt. It was written in three writing systems: Egyptian hieroglyphs, demotic, and Greek, on several ancient Egyptian memorial stones, or steles. The inscription is a record of a great assembly of priests held at Canopus, Egypt, on 7 Appellaios (Mac.) = 17 Tybi (Eg.) year 9 of Ptolemy III = Thursday 7 March 238 BC. Their decree honoured Pharaoh Ptolemy III Euergetes; Queen Berenice, his wife; and Princess Berenice.
Astronomical ceiling decoration in its earliest form can be traced to the Tomb of Senenmut (Theban tomb no. 353), located at the site of Deir el-Bahri, Egypt. The tomb and the ceiling decorations date back to the 18th Dynasty of ancient Egypt. It is closed to the public.