[[Coptic ]] calendar''', also called the '''Alexandrian Calendar''', is used by the Coptic Orthodox Church. It is based on the Ancient [http://en.wikipedia.org/wiki/Egyptian_calendar Egyptian calendar]. Egyptians were the first to calculate time. They divided the year into 12 months, according to their knowledge of the stars. Each of the 12 months was 30 days long, and they added five more days, which they called the 'small month'. Therefore, their year became 365 days long. To avoid the calendar creep of the Ancient Egyptian calendar, a reform of the calendar was introduced at the time of Ptolemy III (Decree of Canopus, in 238 BC), which consisted in the intercalation of a 6th epagomenal (auxiliary) day every fourth year. However, this reform was opposed by the Egyptian priests, and the idea was not adopted until 25 BC, when the Roman Emperor Augustus formally reformed the calendar of Egypt, keeping it forever synchronized with the newly introduced [[Julian Calendar|Julian calendar]]. To distinguish it from the Ancient Egyptian calendar, which remained in use by some astronomers until medieval times, this reformed calendar is known as the Coptic calendar. Its years and months coincide with those of the [[Ethiopian calendar]] [http://en.wikipedia.org/wiki/Ethiopian_calendar], but the latter has different Amharic month names.
==The Coptic year==
==The date of [[Christmas]]==
The choice of [[December 25|25 December]] to celebrate the Nativity of [[Christ]] was first proposed by Hippolytus of Rome (170–236), but was apparently not accepted until either 336 or 364. [[Dionysius of Alexandria]] emphatically quoted mystical justifications for this very choice:
:[[March 25]] was considered to be the anniversary of Creation itself. It was the first day of the year in the medieval Julian calendar and the nominal vernal equinox (it had been the actual equinox at the time when the Julian calendar was originally designed). Considering that Christ was conceived at that date turned March 25 into the Feast of the [[Annunciation]] which had to be followed, nine months later, by the celebration of the birth of Christ, Christmas, on December 25.
==The date of Easter==
According to Christian tradition, Jesus died at the ninth hour (that is, the canonical hour of nona or 'noon' in Middle English - 3:00 pm) of the first full day of Pesach, when that day fell on a Friday; and arose from the dead at or by the first (canonical) hour of that Sunday. The day of Pesach ([[Pascha]] or Passover, Nisan 14), is always at the first or second full moon following the vernal equinox. At the [[First Ecumenical Council]], held in 325 at
Nicaea, it was decided to celebrate Easter on the Sunday following the so-called Paschal full moon. The Paschal full moon is an arithmetical approximation to the first full moon after the vernal equinox. It may be expressed as follows in terms of the so-called Golden number (G) and Century term (C):
*Paschal full moon (PFM) = ([[April 19|19 April]], or 50 March) - (C+11G) mod 30
C is -4 from 1583 to 1699, -5 from 1700 to 1899, -6 from 1900 to 2199, -7 from 2200 to 2299 etc... As the Sunday following the PFM, Easter is one week after the PFM when the PFM happens to fall on a Sunday. One must work with the Julian calendar (C = +3) to find when Easter is celebrated by Orthodox churches.
At the Council of
Nicaea, it became one duty of the Coptic [[Pope]] of Alexandria to determine the exact dates of Easter and to announce it to the rest of the Christian churches (see [http://www.copticcentre.com/copticsaints.html#Pope%20Demetrius%20The%20Vinedresser Pope Demetrius the Vinedresser, 3rd cent.]). This duty fell on this officate because of the erudition at Alexandria he could draw on. The precise rules to determine this are very involved, but Easter is usually the first Sunday after a full moon occurring no sooner than March 21, which was the actual date of the vernal equinox at the time of the First Council of Nicaea. Shortly before Julius Caesar reformed the calendar, the vernal equinox was occurring on the "nominal" date of March 25. This was abandoned at Nicaea, but the reason for the observed discrepancy was all but ignored (the actual tropical year is not quite equal to the Julian year of 365¼ days, so the date of the equinox keeps creeping back in the Julian calendar).
''See also'': [http://en.wikipedia.org/wiki/Computus Computus], [[Julian Calendar]], [[Revised Julian Calendar]]
:Thout also known as Tout is the first month of the Coptic calendar. It lies between [[September 11]] and [[October 10]] of the Gregorian calendar. The month of Thout is also the first month of the Season of 'Akhet' (Inundation) in Ancient Egypt, where the Nile floods cover the land of Egypt. The name of the month of Thout comes from Thot, the Ancient Egyptian God of Wisdom.
:Paopi also known as Baba is the second month of the Coptic calendar. It lies between [[October 11]] and [[November
10]] of the Gregorian calendar. The month of Paopi is also the second month of the Season of 'Akhet' (Inundation) in Ancient Egypt, where the Nile floods cover the land of Egypt. The name of the month of Paopi comes from Hapy, the Ancient Egyptian Nile God.
:Hathor also known as Hatour is the third month of the Coptic calendar. It lies between [[November
11]] and [[December 9]] of the Gregorian calendar. The month of Hathor is also the third month of the Season of 'Akhet' (Inundation) in Ancient Egypt, where the Nile floods cover the land of Egypt. The name of the month of Hathor comes from Hathor, the Ancient Egyptian Goddess of Beauty and Love.
:Koiak also known as Kiahk is the fourth month of the Coptic calendar. It lies between [[December 10]] and [[January 8]] of the Gregorian calendar. The month of Koiak is also the fourth month of the Season of 'Akhet' (Inundation) in Ancient Egypt, where the Nile floods cover the land of Egypt. The name of the month of Koiak comes from Ka Ha Ka, which means Good of Good, a name of the Ancient Egyptian sacred Apis Bull.
* '''Pi Kogi Enavot (Nasii)'''
:Pi Kogi Enavot also known as El Nasii is the thirteenth and last month of the Coptic calendar. It lies between [[September 6]] and [[September 10]] of the Gregorian calendar. That month is also incorporated in the Season of 'Shemu' (Harvest) in Ancient Egypt, where the Egyptians harvest their crops throughout the land of Egypt. The name Pi Kogi Enavot means the little month.
== Sources and external links ==
* [http://www.copticchurch.net/easter.html An introduction to the Coptic calendar] - ''Includes an online Coptic Holidays and Easter calculator''
* [http://www.copticchurch.org/Texts/Spirituals/Coptcaln.pdf '''''The Coptic Calendar and Church of Alexandria''''' - by the Very Rev. Fathers Tadros Y. Malaty and Matta El-Meskeen (PDF)]
* [http://en.wikipedia.org/w/index.php?title=Coptic_calendar Coptic Calendar (Wikipedia)]