The '''[[Coptic]] calendarCalendar''', also called the '''Alexandrian Calendar''', is used by the [[Church of Alexandria (Coptic)|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 latterAncient Egyptian calendar, a reform of the Ancient Egyptian 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 have the latter has different numbers and Amharic month names.

The Coptic year is the extension of the ancient Egyptian civil year, retaining its subdivision into the three seasons, four months each. The three seasons are commemorated by special prayers in the Coptic Liturgy. This calendar is still in use all over Egypt by farmers to keep track of the various agricultural seasons. The (Egypt used the Coptic calendar has 13 months, 12 of 30 days each and an intercalary month at Calendar till the end of Khedive Ismael adopted the year of 5 or 6 days, depending whether the year is a leap year or not. The year starts on Western [[August 29|29 AugustGregorian Calendar]] in the Julian Calendar or on the 30th nineteenth century and applied it in the year before (JulianEgypt's government departments.) Leap Years. The Coptic Leap Year follows the same rules as the Julian Calendar so that the extra month always has six days in the year before a Julian Leap Year.

The Coptic calendar has 13 months, 12 of 30 days each and an intercalary month at the end of the year of 5 or 6 days, depending whether the year is a leap year or not. The year starts on [[August 29|29 August]] in the Julian Calendar or on the 30th in the year before (Julian) Leap Years. The Coptic Leap Year follows the same rules as the Julian Calendar so that the extra month always has six days in the year before a Julian Leap Year. The Feast of Neyrouz marks the first day of the Coptic year. Its celebration falls on the 1st day of the month of Thout, the first month of the Coptic year, which for AD 1901 to 2098 usually coincides with [[September 11|11 September]], except before a Gregorian leap year when it's [[September 12]]. Coptic years are counted from AD 284, the year [[Diocletian]] became Roman Emperor, whose reign was marked by tortures and mass executions of Christians, especially in Egypt. Hence, the Coptic year is identified by the abbreviation A.M. (for ''Anno Martyrum'' or "Year of the [[Martyr|Martyrs]]"). The A.M. abbreviation is also used for the unrelated Jewish year (''Anno Mundi'').

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:

Until the 16th century, 25 December coincided with 29 Koiak of the Coptic calendar. However, upon the introduction of the [[Gregorian calendar]] in 1582, December 25 shifted two weeks earlier in comparison with the Julian and Coptic calendars. This is the reason why [[Old Calendarists]] (using the Julian and Coptic calendars) celebrate Christmas on [[January 7]], two weeks after the New-Calendrists (using the Gregorian calendar), who celebrate Christmas on December 25.

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[[Nicea]], 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):

*When (C+11G) is 1 modulo 30, and G=12, PFM = [[April 17|17 April]] (not 18).

At the Council of NicaeaNicea, 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 NicaeaNicea. Shortly before Julius Caesar reformed the calendar, the vernal equinox was occurring on the "nominal" date of March 25. This was abandoned at NicaeaNicea, 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]]

:Paopi also known as Baba is the second month of the Coptic calendar. It lies between [[October 11]] and [[November 109]] of the Gregorian calendar. The month of Thout 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 1110]] 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.

:Paremhat also known as Baramhat is the seventh month of the Coptic calendar. It lies between [[March 10]] and [[April 8]] of the Gregorian calendar. The month of Tobi Paremhat is also the third month of the Season of 'Proyet' (Growth) in Ancient Egypt, where the Nile floods recede and the crops start to grow throughout the land of Egypt. The name of the month of Paremhat comes from Mont, the Ancient Egyptian God of War.

:Paremoude also known as Barmouda is the eighth month of the Coptic calendar. It lies between [[April 9]] and [[May 8]] of the Gregorian calendar. The month of Tobi Paremoude is also the fourth month of the Season of 'Proyet' (Growth) in Ancient Egypt, where the Nile floods recede and the crops start to grow throughout the land of Egypt. The name of the month of Paremoude comes from Renno, the Ancient Egyptian God of severe wind and death.