The "Nicene Formula" section is misleading. One could infer from it that the council itself gave us the detailed formula involving March 20 and the EFM based on the 19-year lunar cycle. This is simply not true. These details were hashed out in the two centuries following the council. They constitute how the Church came to operationalize the council's decision that Pascha was to be observed on the Sunday following the full moon on or after the vernal equinox. But these details did not come from the council itself.--BALawrence 01:08, June 4, 2008 (UTC)
The article as a whole would benefit from clarification and supplementation. I have prepared an extensive rewrite which I thought it might be more pleasant and efficient to post here first for comments. Only new sections or sections with extensive edits are shown:
§ Paschalion The Paschalion of the Orthodox Church is a set of rules for determining the date of Pascha that traditionally has been implemented by calendrical tables combining Metonic lunar cycles with the Julian solar year. The rules are attributed to the First Ecumenical Council (held at Nicea in 325 A.D.); the cyclical Paschal tables that emerged in connection with the Council were based on 3rd and 4th century Alexandrian prototypes, and then transposed into Julian dates by Dionysius Exiguus in the 6th century. (Citation 1: See http://www.tertullian.org/fathers/dionysius_exiguus_easter_01.htm for the Paschal cycle of Dionysius; and http://en.wikipedia.org/wiki/Dionysius_Exiguus for an account of the transposition.)
§ Early History (last paragraph) The controversy was resolved at the Council of Nicea. Although the decision was not recorded as a canon, its synodal letter to the Church in Alexandria conveys “...the good news of the agreement concerning the holy Easter, ...that all our brethren in the East who formerly followed the custom of the Jews are henceforth to celebrate the said most sacred feast of Easter at the same time with the Romans and yourselves.” (Citation 2: See http://www.ccel.org/ccel/schaff/npnf214.vii.ix.html.)
The Emperor Constantine confirmed this agreement in an epistle to all churches, announcing two things: (1) "...the most holy festival of Easter should be everywhere celebrated on one and the same day. ...[So] cheerfully accept what is observed with such general unanimity of sentiment in the city of Rome, throughout Italy, Africa, all Egypt, Spain, France, Britain, Libya, the whole of Greece, and the dioceses of Asia, Pontus, and Cilicia;" and (2) "We have cast aside [the Jewish] way of calculating the date of the festival [because] ...we should never allow Easter to be kept twice in one and the same [solar] year!" (Citation 3: Eusebius, Vita Constantine III:18-20, Nicene and Post-Nicene Fathers, Vol. 14, pp. 54-55. Also available at http://www.fourthcentury.com/index.php/urkunde-26.)
Thus, the old custom of consulting the Jewish calculation of 14 Nisan and celebrating Pascha on that date was formally rejected, and the independent computations long in use at the influential city of Alexandria became the emerging, if still somewhat controversial, consensus. On the other hand, the comments of canonists, preachers, and chroniclers indicate that the old Quartodecimian custom of placing Easter in the month of Nisan as computed by the Jewish community continued to have adherents for generations.
§ The Nicene Formula The Alexandrian and Roman methods of determining the date of Pascha were based on three principles: (1) Pascha was always after the vernal equinox, (2) it was to follow, but not coincide with, the first full moon of spring, and (3) it was always to be on a Sunday. A fourth principle – and one enunciated following Nicea I – is implicit in the first three: namely, (4) the date of Pascha was not to depend on the Jewish dates for Passover in any way. This last criterion was met by formulating the Paschalion entirely in terms of astronomical events and the weekly cycle of days. (Citation 4: For a fuller discussion, see James Campbell, “The Paschalion: An Icon of Time,” St. Vladimir’s Theological Quarterly, Vol. 28 No. 4 (1984) pp. 245-262.)
One early text that gives an explicit outline of the Nicene formula for dating Pascha is in a homily from 387 A.D. that is attributed to St. John Chrysostom: "Since we keep the first of times [spring], and the equinox [isimera], and after this the fourteenth of the moon, and together with these the three days Friday, Saturday, and Sunday; lacking any of these at one time it is impossible to fulfill the Pascha." (Citation 5: Chrysostom, Paschal Homily VII, Migne, Patrologiae graecae Vol. 59, col. 747A.) In summarizing the Paschalion, the homily makes no reference to any named month – lunar or solar – nor to any calendrical date – Julian or Jewish. Yet there were many tables of computed Paschal dates circulating in the 4th century.
The computational system that eventually prevailed was based on calendrical experiments made at Alexandria beginning in the mid-3rd century. (Citation 6: The basic system can be found in the “Paschal Canon” of the Alexandrian scholar Anatolius, Bishop of Laodicea, which was composed c. 277 A.D. See http://www.ccel.org/ccel/schaff/anf06.vi.iii.ii.i.html and following pages.) According to this system, Pascha is the first Sunday following the date of the Paschal Full Moon (PFM) for a given year. The computational PFM is not, however, as commonly thought, the first full moon following the vernal equinox. Rather, the PFM is the first Ecclesiastical Full Moon (EFM) date that falls on or after March 21 (or, what is the same thing, the first Ecclesiastical Full Moon that follows March 20). Ecclesiastical Full Moons are calendar dates that approximate astronomical full moons using a cycle that repeats every 19 years. March 21 was the date used by the Alexandrians for determining the PFM because it was near the date of the vernal equinox in the late 3rd and early 4th century A.D., when Paschal tables were first being compiled. This conventional, cyclical Paschalion is called Nicene because some commentators in later generations erroneously attributed it to the Nicene Council and came to treat it as canonical.
Nonetheless, the intention of the Nicene Fathers was to establish a simple set of rules that would allow Pascha to be dated independently of the Jewish calendar, and ensure that the basic chronological sequence of Passion and Resurrection as recorded in the Gospels was imitated every year. Insisting on Sunday as the only day suited to commemorating the Resurrection reveals their intention to imitate the chronology of the original event; and their preference for an astronomically determined vernal equinox is evident from the Eastern Church’s early adoption of the Alexandrian Paschal computations based on March 21st rather than March 25th, the conventional date of the vernal equinox on the Imperial Julian and Alexandrian calendars. (Citation 7: Until the 6th century the Paschal tables used in Rome were based on the conventional date of March 25th for the vernal equinox. Jones, “The Development of the Latin Ecclesiastical Calendar” in Bedae, Opera de Temporibus (Cambridge: Medieval Academy of America, 1943), pp. 1-104.)
A thousand years later, the canonist Matthew Blastaris reaffirmed the importance of these four principles in a concise way: "First, that it is necessary to celebrate the Pascha after the spring equinox; second, that it is not the same day as the Jewish festival; third, that it is not merely after the equinox, but after the first full moon following the equinox; and fourth, that [it is] the Sunday immediately after the full moon." (Citation 8: Matthew Blastaris, Syntagma Alphabeticum, Migne, PG 145, 96D-97A.) Blastaris clearly states that it is the equinox and the full moon that determine the proper Sunday, not March 21st Julian - or Nisan 14/15 on the Hebrew calendar. But his second rule is open to misconstrual.
The Nicene Council rejected the Quartodecimian practice of celebrating Pascha on “the same day as the Jewish festival [of Passover]” and adopted three rules that prevent that from happening except by coincidence. Yet Blastaris’ second rule is understood by some to mean that the date of Pascha must be moved in order to avoid coinciding with Passover. (Citation 9: See Agapios and Nicodemus, The Rudder (Pedalion), Masterjohn (tr.) 2006 “Apostolic Canon 7,” p. 115; available at http://orthodoxbahamas.com/wp-content/uploads/2012/01/THE_RUDDER_Copyright__Ralph_J._Masterjohn_2006.pdf.) This reading of Blastaris, however, compromises the independence of the Christian Paschalion from the Jewish festal calendar and lends the so-called “Zonaras Proviso” canonical authority.
§ The Zonaras Proviso The decision of the Nicene council concerning Pascha was that it should be computed independently of any Rabbinic computations: hence, a Paschalion that is consistent with Nicene principles cannot have any built-in dependence on the Jewish calendar.
Nevertheless, since at least the 12th century it has been widely believed that Christian Pascha is required always to follow, and never coincide with, the first day of Passover, which was by then being celebrated on Nisan 15 in the Jewish calendar (that is, on the evening of the 14th day of the lunar month). By the 12th century the errors in the Julian calendar's equinoctial date and age of the moon had accumulated to the degree that Pascha did, in fact, always follow Jewish Nisan 15. This state of affairs continues to the present day, even though the Jewish calendar suffers from a slight solar drift of its own, because the Julian calendar's errors accumulate more rapidly than the Jewish calendar's.
The 12th century canonist Joannes Zonaras seems to have been the first to state the principle that Pascha must always follow Jewish Nisan 15, so the principle is called the “Zonaras Proviso” after him. Upon examination, it appears that Zonaras derived his new rule from a misconstrual of Apostolic Canon 7, which reads as follows: "If any Bishop, or Presbyter, or Deacon celebrate the holy day of Easter before the vernal equinox with the Jews, let him be deposed." (Citation 10: The Rudder, Cummings ed. (Chicago: The Orthodox Christian Education Society, 1957), p. 9. Also, Agapios & Nicodemus, The Rudder, p. 113.)
Zonaras found two prohibitions in this one statement: first, that Pascha must be celebrated after the vernal equinox; and second, that Pascha must never coincide with the Jewish feast of Passover. Although Zonaras’ second prohibition has no foundation in the 4th century historical context, or in the grammatical meaning of the sentence, it resembles the fourth (implicit) Nicene principle closely enough to be confused with it. That is, the rule that Christians are not to go along “with the Jews” in setting the date of Pascha has been confused with the fear that if Passover happens to coincide with an independently determined Pascha, Christians would be wrongfully praying “with the Jews” just because both are praying on the same day.
§ The Byzantine Proposal of 1324 A.D. In the 14th century Nicephoras Gregoras calculated the current error in dating the vernal equinox to be three days, and proposed a reform of the Julian calendar to Andronicus II. The reform was not adopted, apparently from lack of popular or political support; and in fact would have corrected less than half of the seven-day error that actually existed at that time. (Citation 11: See Guiland, Essai sur Nicephore Gregoras (Paris: P. Geuthner, 1926), pp. 282-284. Also, ' 'Dictionnaire de Théogogie Catholique' ' (Paris, 1911) Tome 11, col. 455; and Welborn, Calendar Reform in the 13th Century (Chicago: University of Chicago Dissertation, 1935), p. 31.)
§ The Gregorian Proposal of 1582 A.D. In October 1582, the Roman Catholic Church adopted a major calendar reform designed to correct the Julian calendar's defects. The Julian calendar then in common use was based on an average year of 365.25 days, slightly longer than the mean tropical year of 365.2422 days and the mean vernal equinox year of 365.2424 days. Since 19 Julian years were taken to be equal to 235 lunar months, the average lunar month in the Julian calendar was 29.530851 days, somewhat longer than the astronomical mean synodic month of 29.530589 days. The new calendar eliminated the 10-day drift in the vernal equinox, and the 3-to-4 day deviation in the age of the moon, that had accumulated since the Julian Paschalion had come into use, and laid down rules that would slow the rate of accumulation of errors in the future.
The new calendar was called the Gregorian after its sponsor, Pope Gregory XIII, and Eastern churches was refused to adopt it on the grounds that the new Roman tables sometimes placed Pascha on the day of the vernal full moon, instead of after it as the Nicene principles required. In 1583 A.D the Council of Constantinople forbade use of the new calendar and Paschalion, making adherence to the Julian calendar a test of Orthodoxy in territories where Roman Catholic Uniate churches were being established.
§ The Orthodox Proposal of 1923 A congress of Orthodox bishops meeting in 1923 under the presidency of Patriarch Meletios IV agreed to set Pascha by means of precise astronomical computations referred to the meridian of Jerusalem, using a midnight to midnight day to date the full moon. (Citation 12: M. Milankovitch, "Das Ende des julianischen Kalenders und der neue Kalender der orientalischen Kirchen," Astronomische Nachrichten 220, 379-384(1924).) This agreement was never permanently implemented in any Orthodox diocese. But the Revised Julian calendar, a more accurate version of the Gregorian calendar, which was introduced by the same congress has been adopted by some jurisdictions for celebrating the fixed feasts of the liturgical year.
§ The World Council of Churches Proposal of 1997 A.D. A consultation of Catholic, Orthodox and Protestant delegates met in Aleppo, Syria and issued an agreed statement recommending that all member churches work toward a common method of dating Pascha based on the three original Nicene principles, but employing astronomical observations from the meridian of Jerusalem instead of any cyclical tabular computation. (Citation 13: See World Council of Churches / Middle East Council of Churches Consultation, “Towards a Common Date for Easter” (1997); available at http://www.oikoumene.org/en/resources/documents/wcc-commissions/faith-and-order-commission/i-unity-the-church-and-its-mission/towards-a-common-date-for-easter/index?set_language=en.)
This was essentially the same proposal as that of 1923 A.D., and was not implemented in the proposed year of 2001 A.D. when Eastern and Western dates for Pascha coincided. Resistance to such a reform by Orthodox jurisdictions is apparently rooted in respect for a widespread belief that March 21st Julian was designated by the Nicene Fathers to be the only true vernal equinox, and nourished by persistent fears that changing the received tradition for dating Pascha would endanger the integrity Orthodoxy’s witness to the Patristic Tradition by creating a purely “cosmetic” unity with other Churches. (Citation 14: For an example of this, see Fr. Luke Luhl, “The Proposal for a Common Date to Celebrate Pascha and Easter,” Orthodox Christian Information Center (1997); available at http://orthodoxinfo.com/ecumenism/common_luhl.aspx.)
Here ends the rewrite. I know I've cited my own work once, but it was published in an edited journal thirty years ago so I think it's fair to use it. James C. 12:24, January 2, 2014 (PST)
Unless there are "B.C." dates in an article, I am not sure that we need to use "A.D." -- at least not more than once. The article mentions a bishop being in the fourth century A.D., but it should go without saying that all bishops lived "A.D."
But when we do use it, we should do so according to proper usage by placing the "A.D." before the year, e.g., "A.D. 325." --Fr Lev 06:19, January 3, 2014 (PST)