In 1963, in an appendix to its document on liturgy, the Second Vatican Council advised that hierarchies could, by agreeing to celebrate the Resurrection on an “assigned Sunday” each year, introduce a new way of determining the annual date of Easter.[1] Because Easter, in order to always occur on Sunday, cannot have a “fixed date” like Christmas or Annunciation,[2] some propose that it be assigned to the second Sunday in April much as Mother’s Day is on the second Sunday of May. Another option would be the usage of a Patristic-era Montanist sect that set a fixed date in April as the point from which the next Sunday would be Easter.[3] Since 2014, revered prelates such as Pope Francis,[4] Tawadros II (Coptic Orthodox Pope),[5] Aphrem II (Syriac Orthodox Patriarch of Antioch),[6] and Justin Welby (Anglican Archbishop of Canterbury)[7] have urged Catholic and Orthodox Churches, as well as other Christian communities, to hasten an agreement to celebrate Easter on a Sunday that would be the same (“common”) for all believers.[8]

Proponents of an assigned Easter intend that this common date replace the ancient but continuing practice of determining for each year a “variable” (“moveable”) Easter Sunday date based on calculations that integrate biblical descriptions and laws with the current course of celestial movements. The rule underlying these calculations was operative as early as c.160 in the Sees of Rome and Alexandria and made obligatory for the entire Church by the Ecumenical Council of Nicaea in 325.[9] The rule requires that the Resurrection be celebrated each year on the first Sunday that follows the first full moon that follows the day in the earth’s annual revolution of the sun at which the Vernal (Spring) Equinox occurs.

For over a millennium before the birth of Jesus, and therefore influencing the Sinai Covenant, Egyptian and Hebrew astronomers measured the earth’s relationship to the sun and to the more distant stars (helical and sidereal measurements) during the course of a year to chart vernal and autumnal equinoxes as well as winter and summer solstices. By the fourth century BC, Greek astronomers computed the earth’s axial tilt to predict more accurately these four markers of the seasons.[10] The term “equinox” was devised by Latin-speaking Christian mathematicians of the second/third century who calculated not only each year’s Easter date but also sought to ascertain the year and date of the first Easter.[11]

In various times and places, churches applying the “Nicaean rule” have differed slightly in defining and measuring these astronomical events. Moreover, celestial movements and relationships undergo natural perturbations. Nevertheless, for nearly 2,000 years, hierarchies have used this rule to assure that the four days corresponding to Jesus’ Last Supper, Crucifixion, Entombment, and Resurrection correspond to two sets of circumstances referenced in the Gospels: 1) the day of the week on which each event occurred; 2) the annual occurrence of relationships involving the earth, sun, and moon that the Hebrew scriptures prescribe as the basis for the Sinai Covenant’s calendar(s) and for celebrating the double festival of Passover and Unleavened Bread. With regard to this second point, the Nicaean rule involves conforming to astronomical conditions prescribed in the Hebrew scriptures for Passover and Unleavened Bread. It does not require acceptance of the “fixed” starting date of these two festivals: specified in the Hebrew scriptures as the 14th day of a month known as Nisan (Exodus 12:6), or by its older name Abib (Exodus 13:4-7; 23:15; 34:18; Deuteronomy 16:1-8), or simply as “first month” of the year (Numbers 9:5; 33:3; 2 Chronicles 35:1).[12] Christian conformity to what Hebrew scriptures indicate of occurring celestial phenomena marking these festivals (rather than the day and month specified in those same scriptures) stems from awareness that the Hebrew calendar is not solar but lunisolar and calibrates the new moon that begins 1 Nisan/Abib, not the full moon of Passover, to proximate occurrence of the equinox.

Support for an Assigned Easter

Two main arguments have been offered for abolishing calculation of variable Easter dates. One is that a variable Easter Sunday can occur as early as the third week in March and as late as the second week of May.[13] This long span of possible dates causes not only Easter and Holy Week, but also the course of Lent and Pentecost, to come at times that seem out of season and to conflict in some years but not others with civic practices, academic schedules, and even sanctoral and temporal feasts that have fixed dates on a church’s liturgical calendar.

Another concern is that differences in applying the Nicaean rule result, in most years, in churches diverging over which of two dates for Easter should be observed. The calculation of two different dates is commonly, though somewhat misleadingly, attributed to a church’s preference for either the Julian or Gregorian solar calendar. Those using the Julian include most Eastern Orthodox churches, Oriental Orthodox churches,[14] and “independent” ecclesial bodies within Eastern rite-families.[15] Those using the Gregorian include the Roman Catholic and Eastern Catholic churches, as well as Protestant and Evangelical communities.

This is not, as some have stated, a difference between “East” and “West.” Eastern Catholic churches celebrate Easter according to the same Gregorian-based calculations as Rome. Moreover, the Roman Rite is itself as deeply embraced by Catholics in East Asia and the Pacific Rim as among those of Western Europe, Western Africa, and the Americas. But although there is no “East-West” divide, differences between Catholicism and Orthodoxy in the choice of a solar calendar and, often, in the variable Easter date are perceived by some as highlighting deeper differences in Christology, ecclesiology, and essential disciplines of sacraments. It has been suggested that eliminating the possibility of two different Easter dates will encourage reconciliation on more substantial issues.

If Christians ceased to observe a variable Paschal season based on celestial criteria comparable to those used by Judaism for determining Passover, they would lose a tangible reminder that both faiths are grounded in cosmic relationships created by God.

Support for Variable Easter Calculation

Counterarguments for continuing to calculate variable Easter and Paschal dates, though less well known, may more elegantly cohere with the physical nature of the Paschal mystery and show a deeper respect for the systematic and liturgical theologies of the Catholic and Orthodox Churches that sometimes celebrate Easter on different Sundays.

For example, Protestant, Catholic, and Orthodox scholars meeting at Aleppo Syria in 1997 warned that if Christians ceased to observe a variable Paschal season based on celestial criteria comparable to those used by Judaism for determining Passover, they would lose a tangible reminder that both faiths are grounded in cosmic relationships created by God and incorporated into his liturgical and moral directives in the Hebrew scriptures. Eliminating variable dates for the Paschal season would result in losing sight (literally) of the astronomical dimension of Easter that is shown in its coinciding not simply with a Sunday in springtime but with the fundamental structure of the universe.[16]

Addressing the concern that variable Easter dates conflict with fixed dates on liturgical and civic calendars, the Aleppo meeting advised that interference in life’s more predictable courses by the occurrence of the Paschal season illustrates the “dramatic way in which the Resurrection breaks into the comfortable routines of the world.”[17] Moreover, a remarkably early or late Easter counters a tendency to reduce it to a Christianized springtime festival in which the Resurrection is equated with new life in nature or spiritual rebirth rather than the creation of a new cosmic order. Accordingly, consensus at Aleppo held that the Nicaean rule for calculating Easter’s variable date be retained.

Along with this consensus, however, Aleppo also proposed a way of reducing the frequency of Catholicism and Orthodoxy arriving at a different variable dates. This would involve calculating celestial events directly from astronomical measurements, rather than mediated through the Julian and Gregorian calendars in which mathematical “averages” identified equinoxes and lunar phases. Though this proposal has merit, critics have cautioned that it would yield a span of possible Easter Sundays even broader than those posited by Julian and Gregorian calculations.[18] Attention to this weakness in the counterproposal has undermined consideration of the Aleppo conference’s more fundamental point: that an assigned Easter date overturns a decision by the most important ecumenical council and conforms Easter to time rather than time to Easter.

There are also other reasons to continue calculating variable Paschal dates:

1. New Testament Revelation

Not only Jesus’ Resurrection but the four days that began with his Last Supper and extend into his Crucifixion and Entombment cannot be fully understood apart from their connection to the beginning of the seven/eight-day long[19] Sinai Covenant observance of Passover and Unleavened Bread.

Much recent scholarship emphasizes, in contrast to an early 20th-century academic consensus, that all four gospels were composed by either members of the Twelve Apostles and therefore direct first-person witnesses to all of Jesus’ adult life (Matthew, John) or by those in direct contact with such witnesses (Mark, Luke). The gospels were circulated while members of the original Twelve governed the Church and many more witnesses capable of verifying the texts were still alive.[20] In accord with their early composition, all three Synoptic gospels situate Jesus’ Last Supper on the annually observed “first day of Unleavened Bread” (14 Nisan) and in anticipation of the “Passover” sacrifices (Matthew 26:17; Mark 14:12; Luke 22:7; cf. 1 Colossians 5:7-8).

The common assumption that the Last Supper was a “Passover Seder” that followed these sacrifices is much mistaken. Not only were Seder rituals (e.g., the four cups, the child’s question) established about two hundred years after the lifetime of Jesus,[21] but common interpretation of the Synoptics as placing the Last Supper after the sacrifices of Passover lambs is easily corrected by John’s assertion that the Last Supper was before the observance of Passover (John 13:1). Just as ordained priests of the Jerusalem Temple disagreed over whether a calendar “date” began at sunset or midnight, so too did the Synoptics and John.[22] For the Synoptics the date of Passover (14 Nisan) started as Jesus gathered with the Twelve after sunset and continued through to sunset on the next day. For John, Passover (14 Nisan) did not start until midnight, hours after the Last Supper, though also continuing into the following daylight hours.

John is unequivocal that Jesus died on the cross on the same Friday afternoon that lambs were slaughtered and offered on the Temple’s Holocaust altar by ordained priests (John 19.14). Only when darkness fell that day (introducing 15 Nisan for the Synoptics but continuing 14 Nisan for John) would these lambs be eaten by those who had donated them. The meal included unleavened bread and bitter herbs but not the foods and other protocols of centuries-later Seder celebrations.[23]

John is unequivocal that Jesus died on the cross on the same Friday afternoon that lambs were slaughtered and offered on the Temple’s Holocaust altar by ordained priests.

2. Sinai Covenant and the Julian Calendar

For the Sinai Covenant and for modern Judaism the first “day” of Nisan is the first day of the liturgical year[24] and is determined by two celestial phenomena monitored, in Jesus’ lifetime, by Aaronic priests. One is the Vernal (Spring) Equinox (tekufah Nisan/Abib),[25] the annual date at which the tilt of the earth as it revolves around the sun causes daylight and darkness to be almost of equal length. The other phenomenon is the new moon (rosh hodesh) that, depending on which branch of Judaism one accepts, is either the first to occur after, or closest to, the Vernal Equinox.[26] Since the lunar cycle is 29.5 days, the moon transitions from new to full on 14 Nisan.

It is noteworthy that 14 Nisan is a “fixed” calendar date. But both of the dominant calendars observed in the Sinai Covenant during the lifetime of Jesus, one whose year spanned about 354 days and the other whose annual course was 364 days, ran short of the physical solar year of 365.24 days. To prevent each of the standard 12 months (and the days of observance within them) from misaligning with the seasons in which they had historically originated through divine prescription or intervention, Aaronic priests added blocs of intercalary (leap) days at prescribed intervals.[27]

But shortly before the lifetime of Jesus, Jews and other people of Europe, Africa, and the Middle East began to also use the Julian solar calendar. Formally established by Julius Caesar to begin on January 1, 409 AUC (i.e., ab urbe condita, the number of years since the founding of Rome), the year in which the Julian calendar began is estimated to be 45 BC. This calendar recognized that earth’s revolution around the sun took 365-and-a-quarter days, with each full day containing 24 hours. To accommodate the quarter day and to keep the yearly enumeration of days in line with the seasons, a leap day was to be added every four years. Actually, an error was made at the start when the first leap year was added after the third rather than fourth year. This error accumulated until 4 AD when Emperor Caesar Augustus ordered adjustments that reset the calendar in 8 AD.[28] Intended as a civic, not religious, calendar for the entire Empire, the Julian was adopted throughout the Middle East about nine years before the birth of Jesus, just as Augustus’s correction took effect.

Not only Jesus’ Resurrection but the four days that began with his Last Supper and extend into his Crucifixion and Entombment cannot be fully understood apart from their connection to the beginning of the seven/eight-day long Sinai Covenant observance of Passover and Unleavened Bread at the full moon in springtime.
Image Credit: AB/Wikimedia/Mucio Scorzelli

Efforts among Christians prior to 200 to reconcile feasts of the Sinai Covenant (as specified in the gospels as the context of Jesus’ Last Supper, Crucifixion, Entombment and Resurrection) with Julian dates led to a variety of different approaches. Some held that Christians should simply commemorate events that culminated in the Resurrection by determining when 14 Nisan coincided with a particular Julian date. There were two ways of doing this, each practiced by a branch of the group designated collectively as Quartodecimans (“Fourteeners”).[29] One way was to simply ask neighboring rabbis when their own calculation of 14 Nisan occurred in conjunction with a Julian date. Another way, based on awareness that Jewish communities differed from each other in computing Sinai Covenant feasts, involved Christians observing and calculating for themselves astronomical phenomena required for 14 Nisan that coincided with a particular Julian date. Whichever method was chosen, Quartodecimans would, on the resulting “day,” celebrate the two redemptive acts of Jesus: his death by Crucifixion and his Resurrection to glorified life.

The problem with Quartodecimans relying either on rabbinic or their own astronomers was that observance of the one day that commemorated both Jesus’ Death and Resurrection might be any day of the week. This, however, was contrary to the gospels which specified that four separate days occasioned the Last Supper, Crucifixion, Entombment, and Resurrection, with the Resurrection being on Sunday—literally, the “daylight after the Sabbath” (Mark 16:1; Matthew 28:1; John 20:1). Church leaders recognized that Jesus’ Resurrection is not a symbolic concept or a metaphor.[30] Its occurrence was a physical event in historical time. By the end of the first century, bishops of Rome and of other primatial sees ruled that celebration of the Resurrection conform to specifications in the gospel accounts concerning the day of the week (Sunday) and the concurrence with the third morning of Passover and Unleavened Bread, the two seven/eight-day-observances that began after both the Vernal Equinox and a subsequent full moon.

The problem with Quartodecimans relying either on rabbinic or their own astronomers was that observance of the one day that commemorated both Jesus’ Death and Resurrection might be any day of the week.

Moreover, Jesus’ Resurrection differs from all other miracles recorded in the scriptures. It is not a resuscitation or restoration. It is the first moment of the New Creation—an intrusion into our physical course of time by someone who retained his humanity but in a way that was no longer limited by this universe’s laws of time and space. The celebration of Easter is preceded not only by the Cross but by the Last Supper. Easter is incomprehensible without the realization that Jesus’ crossing of physical universes first occurred at the moment when he told the Twelve that bread had become his body and wine had become his blood. He was standing with the Twelve that night but he was also already present, as he would be after the Resurrection in every eucharistic celebration, under the appearance of what they were to consume.

Because of this emphasis on the historical and physical reality of the Resurrection, Christian scholars contemporary with the Quartodecimans opted for mathematical calculations and astronomical observations that assured that Easter would occur on a Sunday after the full moon that determined the Julian equivalent to 14 Nisan. By the time of Pope Anicetus (pontificate, c. 157-168) there was a tradition in Rome of computing an annual Easter date to occur on a Sunday after the full moon that followed the spring equinox. Although Anicetus tolerated Quartodecimans such as Bishop Polycarp of Smyrna,[31] Rome subsequently became concerned when Quartodecimans from Asia Minor tried to promote their methods of Paschal calculation in Rome. The result was that Pope Victor (pontificate, c. 189-199), despite the urging of Bishop Irenaeus of Lyon to be lenient, excommunicated Quartodecimans in Asia Minor. As modern researcher Thomas Talley concludes, Rome had her own clear idea by 100 of factors to be considered in determining a variable date for Easter but was originally tolerant of methods used elsewhere. Only when Quartodecimans sought influence in Rome did Pope Victor suppress a major center for their ideas. The conclusion: different methods of determining a variable date are acceptable; trying to change Rome’s method is not.[32]

What should also be noted is that Quartodecimans and those who held what would later be the Nicaean rule both represented, despite their differences, the early Church’s commitment to a variable date for Easter.

3. Valuing Both Julian and Gregorian Dates

Despite the claims of some who seek to eliminate variable Easter dates, differences between Catholic and Orthodox churches are not entirely the result of Orthodox preservation of the Julian calendar in contrast to gradual adoption of the Gregorian calendar, between 1582 and 1752, in Catholic and Protestant areas. As early as the century after Nicaea, long before there was a difference of solar calendars in Christian regions, individual churches using the Nicaean rule calculated different variable dates in any given year.[33] Pope Leo I (pontificate 440-461) admitted that Alexandrian priest-astronomers were providing more suitable calculations according to Nicaea’s directive than their counterparts in Rome.[34] In 664, the Synod of Whitby in the British Isles was convened in order to determine the better of two possible applications—one from Rome, the other from Irish monasticism—of Nicaea’s rule. Subsequently, a monk, Venerable Bede (673-735), supplied a mathematical treatise to support Whitby’s conclusion that Rome offered the more accurate method of calculating the variable Easter date.[35]

Shortly before the lifetime of Jesus, Jews and other people of Europe, Africa, and the Middle East began to also use the Julian solar calendar. Formally established by Julius Caesar to begin on 1 January 409 AUC (i.e., ab urbe condita, the number of years since the founding of Rome), the year in which the Julian calendar began is estimated to be 45 BC. Efforts among Christians prior to 200 to reconcile feasts of the Sinai Covenant, as specified in the gospels as the context of Jesus’ Last Supper, Crucifixion, Entombment and Resurrection, with Julian dates led to a variety of different approaches.
Image Credit: AB/Wikimedia

The introduction of the Gregorian calendar is often misrepresented. First of all, it was authorized in 1582 by Pope Gregory XIII because of a mathematical miscalculation of the frequency with which “leap” days needed to be added to the Julian calendar. This was not a repeat of the simple error that Augustus had corrected by 8 AD. Instead the problem stemmed from a fundamental astronomical measurement. Because earth’s revolution around the sun takes 365-and-one-quarter days, the Julian calendar added a leap day every four years. Unfortunately, the “one quarter” was not .25 of a day but actually .24. What would become a problem—though not evident until centuries passed—was that the Julian calendar added leap days too often. Because the estimated 365.25 days assumed by the Julian calendar were actually 365.24 days in the astronomical cycle, a leap day every four years had resulted in the physical reality to which certain calendar dates were originally calibrated occurring at progressively earlier calendar dates. Called “regression,” this was a particular problem for the solstices and equinoxes. For example, during Jesus’ lifetime, the Vernal Equinox was March 25 on the Julian calendar. When Nicaea was held (325) regression brought that equinox to the Julian date of March 21.[36] By the 16th century, the Vernal Equinox occurred on March 11. Thus Pope Gregory’s staff of astronomers dropped 10 days from the 1582 calendar (to set the date of the equinox to what it was at the time of Nicaea not the full 14 days to March 25) and decreed that in the future, though leap days would continue to be added every four years, the extra day would not be added if the year’s enumeration was evenly divisible by 100, unless it was evenly divisible by 400.

What should be noted is that the Gregorian was not a “new” calendar. It was simply a correction of the Julian that accomplished more accurately what the Julian was intended to do. Moreover, the Gregorian is not a “Western” calendar in contrast to an “Eastern” Julian. Both calendars originated in Rome.

One matter that perplexes many is that the calculation of variable dates for Easter involves the choice of a solar calendar with which to calculate and upon which to project the results of observing and measuring the appropriate celestial phenomena. The two solar calendars—Julian and Gregorian—sometimes yield a single date for Easter in a particular year. This happened most recently on April 16, 2017 and will occur again on April 20, 2025. But even in years when Julian and Gregorian calculations arrive at a single Easter date, the date can be projected on a Gregorian (New Style = NS) or Julian (Old Style = OS). Thus April 16, 2017 and April 20, 2025 are the dates that appear on a Gregorian (NS) calendar. But on a Julian (OS) calendar they would appear as, respectively, April 3, 2017 and April 7, 2025 even though each of those OS dates occurs on the same “day” as its corresponding NS date.[37] In most years, however, Julian calculations and Gregorian calculations result in two completely different Easter dates. Here the complexity of the problem referred to above, regarding which solar calendar to calculate with and which to project the results upon is further exacerbated. For example, in 2021 the Resurrection was celebrated on April 4 by those using Gregorian-based calculations and projecting the result on a Gregorian (NS) calendar. But in the same year those whose paschal calculations (Paschalion) are Julian but who project this on a Gregorian (NS) calendar celebrated Easter on May 2. For those communities whose Julian calculation was also projected on a Julian calendar, the May 2, 2021 NS date was expressed as April 19, 2021 OS, though both May 2 NS and April 19 OS occurred on the same “day” that year.

Yet over the centuries, in the years in which Christians arrive at two different Easter dates (or simply designate that date differently as has just been shown), there has been no animosity or ridicule. The appearance of different dates for Easter in some years has been a model of inter-religious graciousness. In fact the only times when there have been schisms and protests is when, as in the case of the Orthodox churches in 1924, some have attempted to change long-standing traditions of calculation and calendar use.[38]

The basic rule for calculation of a variable date Easter carries the theological and ecclesiastical weight of having been required authoritatively for all Christians by Nicaea. There is no council more important or more ecumenical than Nicaea.

4. Comparing Conciliar Decisions

Although it has been recognized, notably in the ecumenical meeting at Aleppo in 1997, that the basic rule for calculation of a variable date Easter carries the theological and ecclesiastical weight of having been required authoritatively for all Christians by Nicaea, this point needs to be given greater emphasis. There is no council more important or more ecumenical than Nicaea. Its directive regarding Easter calculation that was appended to its canons represents a decision by the same council Fathers who defined the eternal divinity of the divine Son and provided terminology to explain his eternal consubstantiality with the Father. The reality of the Resurrection is most fully understood in terms of Nicaea’s Trinitarian theology: Jesus rose from the dead as the same divine Person who is consubstantial with the Father but who has permanently become man. It is he who now stands with both his divinity and humanity intact, but with his humanity having attained a different quality of physicality in the Resurrection. The gospels recount how Jesus did things after the Resurrection that he did not do before: he walks into locked rooms and appears instantaneously. The Letter to Hebrews affirms that it is this resurrected (glorified) human body of Jesus that stands before the Father as God and man to officiate as high priest in the heavenly sanctuary (Hebrews 8:1-6; 9:11-14). It is also this living, resurrected body and soul, as well as divinity, who is received in the Eucharist.

As for the Second Vatican Council’s reference to assigning a Sunday for the celebration of Easter, it is noteworthy that this provision is merely the acceptance of the possibility of doing so with the caveat that the decision needs to be universal. Unlike Nicaea which mandated the basics of a variable-date calculation (though not the conclusions that might be reached), Vatican II did not mandate use of an assigned date.

Physics and History—and Theology

Instead of being the “axis” of the liturgical year, around which all other seasons are configured, an assigned Easter Sunday would become just another solemnity.

It is common to speak of the “moral of the story.” What has been offered in this essay is a “conclusion from the physics and the history.” Assigning a “common” Easter Sunday will destroy a commitment that Christians have valued for centuries. And, again, one should not be discarding the gospel emphasis on the link between Passover/Unleavened Bread and Easter. Nor should one depart from the true and foundational ecumenism established by Nicaea’s requirements for a variable date.

The real issue is this: eliminating the calculation of variable dates for Easter would bypass conceptual and physical realities that truly unite believers in Jesus and are essential to their common faith. The first of these realities is the gospel record specifying that Jesus’ Last Supper, Crucifixion, Entombment, and Resurrection took place in historical time in conjunction with prescribed celestial phenomena for Passover and Unleavened Bread. The occurrence on specified days of the week in the last week of Jesus’ temporal life was itself the result of observing and computing earth’s relationship to solar, sidereal (more distant stars), and lunar phenomena. The second reality is that the biblical theology of the Resurrection, and of the entire Paschal season, is not simply analogous to the naturally recurring cycle of “new life” at springtime. Nor is it a mere miracle that changes the course of nature (like walking on water or reviving Lazarus). Instead, the Resurrection is a fundamental change in the physical world that establishes new laws of time, space, and matter.[39]

Instead of being the “axis” of the liturgical year, around which all other seasons are configured, an assigned Easter Sunday would become just another solemnity.

On the other hand, arguments for a “common” Easter date are entirely practical and without theological definition. They also omit mention of biblical, historical, scientific, and ecumenical contexts. Pressure to abandon a system that has served Christians, though in different ways, for many centuries and which is based on a careful understanding of the meaning of the Resurrection principles, may cause more turmoil in the future than humble recognition that some divisions among Catholics and Orthodox are not resolvable. This conclusion regarding a different controversy was reached in 1999 after intense discussions by Lutheran and Catholic theologians concerning the concept of “Justification.” Although the discussions resolved some misunderstandings on each side concerning what the other side’s teaching involved, the conclusion that both sides ultimately accepted was that Catholic and Lutheran methods of biblical exegesis and theological analysis had drawn conclusions about Justification that could not be reconciled. Coming up with unifying terminology would merely obscure a genuine and sincere disagreement. As the Joint Declaration on the Doctrine of Justification” stated:

“The understanding of the doctrine of justification set forth in this Declaration shows that a consensus in basic truths of the doctrine…exists between Lutherans and Catholics. In light of this consensus the remaining differences of language, theological elaboration, and emphasis in the understanding of justification…are acceptable. Therefore the Lutheran and the Catholic explications of justification are in their difference open to one another and do not destroy the consensus regarding the basic truths.”[40]

In other words, humbly accepting that another’s position is irreconcilable with one’s own can show greater mutual respect than artificial signals of a unity that does not exist. Proposals to change the determination of Easter should be respectfully dismissed as were the proposals to redefine Justification.


Any websites cited below were accessed between April 17 and June 5, 2021.

  1. Second Vatican Council, Constitutio de Sacra Liturgia: Sacrosanctum concilium (December 4, 1963) AAS 56 (1964) Appendix 133-34.

  2. A “fixed date” (e.g., March 25 for Annunciation/Incarnation) has the same enumeration every year but can fall on any day of the week. Though English translations (including those on the Vatican website) cite Sacrosanctum concilium as proposing a “fixed” Easter date, the words are actually dominica assignando (assigned Sunday). The word “fixed” also mistranslates the phrase unico die (single day) in Orientalium Ecclesiarum #20 (November 21, 1964) AAS 57 (1965) 82.

  3. Sozomen (c.400-450), Ecclesiastical History: A History of the Church in Nine Books (London: Bagster, 1846) 353-54.

  4. J. Burger, “Pope Francis Calls for One Date for Easter” Aleteia, June 22, 2015.

  5. S. Zaimov, “Coptic Orthodox Pope Tawadros Suggests One Easter Date for All Churches in Letter to Pope Francis” Christian Post, May 8, 2014.

  6. L. Ieraci, “Pope, Orthodox Patriarch Express Commitment for Unity,” Catholic News Service, June 19, 2015.

  7. B. Quinn, “Christian Leaders Attempt to Fix [sic] Global Date for Easter,” Guardian, January 15, 2016.

  8. Kurt Cardinal Koch (President, Pontifical Council for Promoting Christian Unity) and Ukrainian Orthodox Abp. Job Getcha (Patriarchal Exarch for Orthodox Parishes of Russian Tradition in Western Europe) advised adoption of a common date in time for Easter in 2025. Catholic News Agency, March 12, 2021. Reprinted Adoremus, May 17, 2021.

  9. The rule was issued as an appendix to its canons. Nicaea noted that these basic principles of Paschal calculation were already used by Rome and Alexandria and by “us” (i.e., Constantinople). Decrees of the Ecumenical Councils, ed. Norman P. Tanner, S.J. (English translation facing Greek/Latin texts; 2 vols.; London: Sheed & Ward, 1990) 1.6.

  10. Equinoxes occur twice in the course of the earth’s annual revolution around its sun. As earth makes this revolution (orbital axis), it also spins on its own axis (rotational axis). In this rotational axis, earth’s north and south poles manifest an “axial tilt” (obliquity) of about 23.43o alternately turning one pole toward the sun and the other away as earth rotates. This causes the solar year to be “tropical” in that the sun appears over the “tropic of Cancer” (a latitude north of the equator) in June (Summer Solstice) and the “tropic of Capricorn” (a latitude south of the equator) in December (Winter Solstice). At both the Vernal (Spring) and Autumnal (Fall) Equinoxes, the sun appears at zenith over the equator. Stanley Wyatt, Principles of Astronomy (2nd. ed., Boston: Allyn and Bacon, 1971), 37-48.

  11. Mathematical calculations to ascertain each year’s variable date of Easter, as well as the place on the Julian calendar of the Passover and Unleavened Bread observance in the year of Jesus’ death were increasingly refined and perfected in the 230s and 240s. Writings such as those of Julius Africanus (d. 240 AD) and the anonymous author of De pascha computus (243 AD) indicated the deep interest, especially among Latin-speaking Africans who valued their ecclesial connection with the Church in Rome, in assuring a correct variable date.

  12. Passover could be postponed to the 14th day of the month after Nisan if time were needed for the ordained priests to carry out purifications (2 Chronicles 30:3, 15). But more commonly Passover was postponed if use of a Sinai Covenant lunar calendar of 354 days caused the month of Nisan to fall too early in comparison to the 365 day tropical/solar year. This was done by inserting, every two or three years, an intercalary month (Second Adair) before Nisan. If the Sinai Covenant in use was the 364 day “priestly” version, regular addition of an intercalary day or days was sufficient.

  13. Easter was celebrated on March 23 in 2008 by those using Gregorian calendar dates in calculating celestial phenomena, and also in applying those dates to the Gregorian (New Style=NS) calendar. The earliest date for Easter in a Gregorian year was March 21 in 1666. Easter occurred as late as May 8 in 1983 for those who, though using Julian calendar dates for calculation, reconciled this to a Gregorian (NS) calendar. For those using the Julian calendar both for calculating and applying a date for Easter Sunday for 1983, the celebration date was April 25 OS which is the same “day” as May 8 NS.

  14. “Oriental” Orthodox churches differ from Eastern Orthodox and from Catholicism by rejecting the explanation of the “two natures” (divine and human) of Jesus that was affirmed by the Ecumenical Council of Chalcedon in 451.

  15. Some “particular” churches within Orthodoxy use the Easter date accepted by non-Orthodox neighbors. For example, Finland’s Eastern Orthodox Church, asserting independence from Russian Orthodoxy, celebrates Easter according to the date used by Lutherans, who in turn follow Catholicism’s “Gregorian” date of Easter. Among Oriental Orthodox churches, Armenians in general follow Rome’s dates but the Armenian Patriarchate in Jerusalem observes dates accepted by most Eastern Orthodox churches.

  16. World Council of Churches, “Toward a Common Date for Easter,” World Council of Churches/ Middle East Council for Churches Consultation, Aleppo, Syria. March 5-10, 1997.

  17. Ibid.

  18. This is because astronomically (sidereally) calculated equinoxes can be set to one date earlier or later than those measured by observation of the earth and sun.

  19. Ambiguity as to whether Passover/Unleavened Bread lasted for seven or eight days stems from whether the observance’s beginning and ending days are included in an enumeration. This is further complicated by disagreement within biblical Judaism as to whether a calendar date begins at sunset, midnight, or sunrise.

  20. Recent research emphasizes that all four canonical gospels, including John, were composed before 66-67. See, for example, Richard Bauckham, Jesus and the Eyewitnesses: The Gospel as Eyewitness Testimony (Grand Rapids: Eerdmans, 2006).

  21. Baruch M. Bokser, The Origins of the Seder: The Passover Rite and Early Rabbinic Judaism (Berkeley: University of California, 1984) xi and Joshua Kulp, “The Origins of the Seder and Haggadah” Currents in Biblical Research 4.1 (2005) 109-134.

  22. Even Joachim Jeremias, who (mistakenly) characterizes the Last Supper as a Seder and rejects the suggestion in John’s Gospel that the starting date of Passover (14 Nisan) began after the Last Supper and continued into the next afternoon, admits that ordained priests of the Second Temple disagreed over the point in each 24-hour period that began/ended a calendar date. The Eucharistic Words of Jesus (London: SCM/Trinity, 1966, repr. Eugene, OR: Wipf and Stock, 2001) 125-137. Roger T. Beckwith notes that biblical-era Jewish belief that daylight or movement toward daylight (rather than sundown) began a calendar date is suggested in Genesis 1:14, 16, 18; Wisdom 10:17; Tobias 10:7; Baruch 2:25; and 2 Maccabees 13:10 and also in Qumran (1 QS 10.1). Calendar and Chronology, Jewish and Christian (Leiden: Brill, 2001) 6.

  23. As Thomas J. Talley notes: “While it has been easy at times in the past to dismiss this Johannine chronology as conscious theologizing of little historical merit, more recent exegetical opinion has been less inclined to reject the historicity of the Johannnine chronology. It seems safe to say that 1 Corinthians 5.7 reflects Paul’s familiarity with a tradition in the primitive Church predicated upon the chronology that we know as Johannine. Indeed…the early celebration of Pascha by Christians seems to presuppose that chronology.” The Origins of the Liturgical Year (2nd ed.; Collegeville: Liturgical Press, 1991) 3-4. See also Lynne Boughton, “The Priestly Perspective of the Johannine Trial Narratives,” Revue biblique 110 (2003) 517-51.

  24. The ancient practice in the Sinai Covenant was to start the year at the Vernal Equinox with Nisan being the first month. This continued into the lifetime of Jesus and remains the practice in modern Judaism for their liturgical year. Jewish policy of beginning the civil year at the Autumnal Equinox began under Seleucid influence in the fourth century BC. Emil Schürer, The History of the Jewish People in the Age of Jesus Christ (175 BC- AD 135), Volume 1, tr. John Macpherson (Edinburgh: T&T Clark, 1890), 36-46.

  25. The Hebrew word tekufah literally means “season.” Thus tekufah Nisan/Abib denotes the Vernal Equinox that ends winter and signals the beginning of spring (2 Samuel 11:1; 2 Chronicles 24:23); tekufah Tammuz denotes the Summer Solstice; tekufah Tishri denotes the Autumnal Equinox; and tekufah Tevet denotes the Winter Solstice.

  26. Some maintain that Sinai Covenant authorities in the era of the Second Temple and into the earliest Christian centuries set 1 Nisan/Abib to the new moon closest to the equinox. Others hold that 1 Nisan coincided with the first new moon after the equinox. The reason for disagreement is Deuteronomy 16:1 which states: “Observe the month of Abib by keeping the Passover of Yahweh your God since it was in the month of Abib that Yahweh, your God, brought you out of Egypt by night.” What is unclear is whether this means that the whole “month” of Nisan/Abib should follow the Vernal Equinox or only 14 Nisan/Abib, the date of Passover, should follow the equinox.

  27. The variety of Sinai Covenant calendars in the era of the Second Temple is noted by Emil Schürer, The History of the Jewish People in the Age of Jesus Christ (175 BC-AD 135), Volume 2 (rev. ed., Geza Vermes and Fergus Millar; Edinburgh: T&T Clark, 1973), Appendix 3; E. Ratzon and J. Ben-Dov, “ A Newly Reconstructed Calendrical Scroll from Qumran in Cryptic Script” JBL 136.4 (2017), 905-36.

  28. T.C. Skeat, The Reign of Augustus in Egypt: Conversion Tables for the Egyptian and Julian Calendars 30 BC-14 AD (MBPAR 84: Munich: Beck, 1993).

  29. Among Quartodecimans was Melito, Bishop of Sardis (Asia Minor) who composed Peri Pascha c. 165 AD/CE.

  30. The physical reality of Jesus’ Resurrection is noted c. 180, Irenaeus, Against heresies 5.31-1-2.

  31. Eusebius, Bishop of Caesarea reports in Ecclesiastical History 5.23-24 (326) that Polycarp claimed these ideas were based on the practice of the Apostle John even though they are inconsistent with a correct interpretation of dates in John’s Gospel.

  32. Talley, Origins 18-27.

  33. Charles von Hefele, A History of the Christian Councils from the Original Documents: To the Close of the Council of Nicaea, A.D. 325, tr. William Clark (2nd ed.; Edinburgh: T&T Clark, 1883) 1.326-27.

  34. Leo I, “Letter to Emperor Marcian” PL 54.1055. Ambrose, Bishop of Milan, and Cyril, Archbishop of Alexandria, made similar observations. This may be why fifth-century Latin translations of Nicaea’s decrees add that the Archbishop of Alexandria was to provide the calculation of the Easter date to the Roman pontiff. Hefele, History 1.328.

  35. Venerable Bede, The Reckoning of Time, tr. Faith Wallis (Liverpool: Liverpool University, 1988).

  36. Currently in the Gregorian calendar, the Vernal Equinox is March 19 or 20 and the Autumnal is September 22 or 23. Variations of a day or two each year in modern calculations represent time zone differences and slight perturbations in earth’s movement.

  37. Most Orthodox churches, which use a Julian calendar Paschalion to calculate the date of Easter but which follow the Gregorian (NS) calendar for both the civic year and most of the liturgical year, experience variable Easter dates on the Gregorian calendar. A few Orthodox churches, which use the Julian calendar not only for calculating the Easter date but also for the whole liturgical year, posit Easter dates on the Julian calendar (OS). For example, in 2019, the Julian Easter date of April 15 OS was the same “day” as Julian April 28 NS, though seven “days” after the April 21 date that was both calculated with, and projected upon, a Gregorian calendar. Though a Gregorian calculation of Easter can be plotted on a Julian calendar (OS), this is rarely done. For calibration of Julian and Gregorian Easter dates to OS and NS calendars see “Side-by-Side Easter Calendar Reference for the 21st Century,”

  38. In 1924 the Patriarchate of Constantinople set its liturgical year to the Gregorian calendar but retained the Julian to determine the Paschal season and Lent. Although many Orthodox adopted this method, others entered into schism.

  39. Thomas Torrance, Space, Time, and Resurrection (Grand Rapids: Eerdmans, 1976; reprint, London: T&T Clark, 2019), 86.

  40. Lutheran World Federation and Catholic Church, “Joint Declaration on the Doctrine of Justification” (1997) #40.