Holy Trinity Cathedral - Ecclesiology

The date of Pascha
the reason for the differences between the Western and Eastern Christians

Nicholas Ossorguine

Instructor in Liturgics

St Sergius Orthodox Theological Institute, Paris

From the earliest days, man’s perception of time was naturally linked with some repeatedly occurring natural phenomena. Thus, for example, the regular change of light and darkness became expressed as a unit of time: a day (a phenomenon determined by the earth’s rotation about its own axis). The regular changes in lunar phases (the rotation of the moon around the earth lasting approximately thirty days) gave rise to the concept of a month. And finally, the regular changes of the year’s four seasons — spring, summer, autumn, and winter — was understood as a yearly cycle consisting of 365 (or 366) days, coupled to the earth’s complete revolution around the sun, which is called the Tropical or Solar year.

Only the seven-day cycle, the constantly repeating seven days of the week, is not based on any natural or other occurrence but has its origin in the creation of the world according to the Biblical narrative. The seven-day cycle was strictly observed by Old Testament Jews as something established by God Himself, and this was continued by New Testament Christians. It can be stated that this cycle was never interrupted and that calendar reforms had no effect on the seven-day week either in the Old or New Testaments.

The Church cycle of fixed feasts (Christ’s Nativity and others) depends exclusively on the solar year. The feast of Pascha, with the season of movable feasts related to it, is determined in accordance with all three cycles: namely, the solar, lunar and the weekly.

Pascha is the greatest Christian feast. The Orthodox Church, in the words of St John Damascene (VIII c), calls it “the feast of feasts, holy day of holy days” (Paschal Canon, Irmos of the Eighth Ode). This was the first Christian feast that was celebrated in Apostolic times. This feast is of such significance that the day of the week during which the Resurrection of Christ took place is forever identified with it. In the Russian language this day is even called Voskresenie [Resurrection]. Throughout the whole Church year, it serves as a constant, weekly reminder of the Paschal feast itself. One particular Sunday of the year is dedicated to this feast of Resurrection. And this is the day, when there is a particular alignment of the Sun, Moon and Earth. At this point, the latter enjoys a time of maximum illumination from the light sources that surround it.

In Orthodox liturgy, light has an exceptionally important meaning. The very word “light” and its derivatives are frequently found in liturgical texts. Christ Himself is the source of true Light “I am the Light of the world” (John 8:12). In this context, solar light is understood as an image of the true Light.

The Christian Church, apparently from Apostolic times, began to fix the date of Pascha (Sunday) precisely in relation to light. For example, the feast of the Nativity of Christ (IV c.) was fixed as December 25, the day of the Winter solstice when sunlight begins to increase. (It was also a pagan feast for the same reason.) As for the sacred day of Pascha, here the moon also plays a part.

The Sunday of the year that falls immediately after a full moon when it occurs not earlier than the vernal equinox is set aside as the feast of Pascha.

Astronomically, the vernal equinox corresponds to that moment in the year when throughout the world (in both hemispheres) the length of the day and the night is equal and the Polar nights end. The significance of this phenomenon is that at this time of the year there is no place on Earth that is not touched by the light of the sun during the day. With the coming of the full moon during this time, the moon, being in the dark half of the Earth’s sphere, reflects the sun’s light, and thus the whole world is surrounded at that moment by the light of the sun.

Thus, in the cosmic aspect, the day of Holy Pascha is determined by the special position of the celestial bodies that illumine the Earth. This special position becomes a “cosmic icon” of that, which the Church describes by the words of the Paschal Canon: “Now all is filled with light: heaven and earth and the lower regions” [Troparion, Ode 3], or “This is the bright and saving night, sacred and supremely festal. It heralds the radiant day of the Resurrection on which the timeless light shone forth bodily from the tomb for all” [Troparion, Ode 7].

In the Church’s consciousness, the foundation of this “cosmic icon” was established by God Himself, the Creator of the world, when, at the coming of the fourth day, He ordered the “two great lights” to illumine the Earth on either side (days and nights) “And God said, Let there be lights ... to divide the day from the night; and let them be for signs, and seasons, and for days, and years; and let them be for lights … to give light upon the earth … made the two great lights; the greater light to rule the day, and the lesser light to rule the night” (Genesis 1:14-16).

Since the First Ecumenical Council (325 AD), this principle for determining the Paschal date (nearest Sunday after the first full moon occurring no earlier than the vernal equinox) was the mandatory rule for the whole Christian Church and remains so even to this day, both for the Eastern and Western Christians.

As for the theological significance of this “cosmic icon” that determines the date of Pascha, there is a little-known Fourth century Greek document (“Anatolian Sermon on the Paschal Date”, 387 AD), which gives a detailed explanation of this significance. The author points to the existing intimate connection between the “seven-day” creation of the world and the “seven-day” redemptive act of Christ.

The creation of the first man, Adam, was followed by his fall and with this the corruption of all creation. Christ, the New Adam, redeems the sin of the first man and brings to life a new creation. In this theological context, the cosmic phenomena (vernal equinox and the full moon that follows it) constitute natural signs that correspond to the beginning of time, when God created the world. The “cosmic icon” of light becomes the icon of the beginning of time at the creation of the world.

The moment of the vernal equinox is the image of the first day of creation. This is the first day, or “day one,” when God gave light to the world and divided the light from the darkness into equal parts, calling them respectively, Day and Night [Genesis 1:3-5]. Let us note that, according to the seven-day sequence, this day corresponds to Sunday, the day of Resurrection. The full moon, which follows it, is an image of the fourth day of creation (as noted above), when God, employing the created heavenly lights, distributed the light (which appeared on the first day) throughout the whole world. Darkness is gradually overcome. The moon’s role is that through it, the light penetrates the realm of darkness as a forerunner of the final victory.

On the sixth day of creation, which corresponds to Friday, God creates the first man, Adam, who fell away from God. Thus the New Adam, Christ, redeems Adam’s sin on the Cross on Holy and Great Friday. On the seventh day, Great and Holy Saturday, while bodily resting in the tomb, He destroys the kingdom of darkness. And on the following day, the first day of the week, which corresponds in this sequence to “day one” when God gave light to the world, the resurrected Christ gives the world the never-setting Light of His Resurrection.

The Gospel reading for the Paschal Liturgy proclaims this mystery: “In the beginning was the Word ... and the Word was God. … All things were made by Him. … In Him was life; and the life was the light of men. … The light shineth in darkness and the darkness comprehended it not” (John 1:1,3-5).

As for the significance of the Hebrew Pesach in determining the time for the celebration of the Christian Pascha, the Fourth century document noted above mentions the day of Pesach only to say that in no event is it to be considered in determining the time of the Christian Pascha. Furthermore, the document’s author includes among the known groups of heretics those Christians who, in calculating the Paschal date, take their cue from Pesach. Some of these heretics, the Quatrodecimanians, observe Pascha on the same day as the Jews, others, the Novatians, observe Pascha on the first Sunday after Pesach.

The idea that the Christian Pascha must always be observed following the Hebrew Pesach was advanced by Byzantine canonists during the time preceding the introduction of the Gregorian calendar in the West (1583 AD). Apparently it was done in an attempt to discredit this forthcoming “Catholic” calendar reform. In essence, prior to the calendar reform in the West, the Hebrew Pesach de facto always preceded the Christian Pascha for entirely technical reasons of the calendar. The Christian and Hebrew calculations were based on the same astronomical data to which the Julian calendar was linked. However, this did not constitute a sufficient reason to make this a mandatory condition.

For the Fathers of the Fourth century, the vernal equinox was the primary determinant for calculating the date of the Paschal feast. The Seventh Apostolic Canon reads: “If any bishop, presbyter or deacon shall celebrate the holy day of Pascha before the vernal equinox, with the Jews, let him be deposed from the holy ranks.” Thus the time of the vernal equinox determines the full moon after which, on the first Sunday following, the Pascha should be celebrated. This moon is the full moon of the Old Testament Pesach.

The Old Testament Pesach, according to Mosaic Law, is linked to the Spring full moon. As confirmed by the Fourth century document, mentioned above, the Hebrew Pesach during the pre-Christian era always occurred after the vernal equinox. With the coming of Christianity, this rule was not always followed, i.e. the Hebrew Pesach could occur prior to the vernal equinox, which served as the reason for the promulgation in the early epoch of the Seventh Apostolic Canon cited above. In this connection, a distinction should be made between the Old Testament Pesach and the Hebrew Pesach of New Testament times. The first one guided Israel to Christ, Who transformed it into the Christian Pascha. The second one, which does not comprehend Christ, lost all significance and, therefore, can have nothing in common, in any relationship, with the Pascha of Christ.

Thus the Christian Pascha, which follows the Old Testament Pesach’s full moon, can never coincide with it or precede it. Today, in the era of the New Testament, whether the full moon corresponds with the present Hebrew Pesach or not, can have no bearing on the Christian Pascha. As an example, let us note that if the first (Paschal) full moon following the vernal equinox does not correspond with the moon of the Hebrew Pesach, it means that the latter is based upon another full moon, either one which precedes or one that follows the first full moon. Neither of these would be of significance for the Christian Pascha since one of them is the second moon that follows the vernal equinox and the other one precedes it.

As for the variation in Paschal dates between Eastern and Western Christians, this occurs solely upon the difference between the calendars that they use: the Julian for the Eastern Church’s Pascha (the so-called “old style”) and the Gregorian for the Western Church’s Pascha (“new style”).

It can be assumed that one century after the First Ecumenical Council (325 AD) an agreement was reached throughout the Christian world on the time for celebrating Pascha. Tables for calculating the Paschal date were prepared based on the calendar in use at that time, and Paschal dates were expressed according to the Julian calendar in conjunction with its March 21st date as the date of the vernal equinox (the Paschal boundary). The Eastern Church used the so-called Paschalia compiled in approximately  the Sixth century. This Paschalia remains in use in the Eastern Church even to this day.

Thus Pascha was celebrated throughout the Christian Church more or less simultaneously until 1583 AD when the calendar reform of Pope Gregory XIII took place in the West. By then, it had been observed for some time that the Julian calendar had fallen behind the solar time by approximately one day every 128 years and by the end of the Sixteenth century this lagging behind amounted to ten days since the time of the First Ecumenical Council in 325 AD. According to the calendar, the actual vernal equinox no longer took place on the 21st of March but on the 11th. As a result of this calendar reform (more precisely, its correction or adjustment) all calendar dates were moved forward by ten days (Friday October 4 was followed by Saturday the 15th), and in order that the calendar would no longer deviate from solar time, it was decided that during every 400-year period three of the leap years would be replaced by normal years, meaning that the date of 29th February would be dropped. The following rule would be applied: only those century leap-years will retain February 29th that can be divided by 400 without a remainder. Thus, 1600 was a leap-year, but the three following century-years, 1700, 1800, and 1900, were not leap-years, even though according to the Julian calendar they were. These different approaches resulted in today’s 13-day difference. Appropriate corrections were made for the calculation of Pascha inasmuch as the Paschal boundary of March 21st was moved by ten days, and from that time the Western Church frequently celebrated Pascha earlier than the Eastern Church, which continued to calculate its date in accordance with the old Paschalia.

When the Western Pascha does not coincide with the Eastern, the difference can be either one week or as great as four or five weeks. This happens because the vernal equinox, according to the Julian calendar that serves as the basis for Paschalia calculations, occurs thirteen days behind the actual one, followed by the Gregorian calendar. Thus March 21 according to the New Style (March 8 Old Style) is the vernal equinox. Western Christians consider this the beginning of the Paschal moon. Thirteen days later, on April 3 New Style (March 21 Old Style) begins the time for calculating the Paschal moon for the Eastern Christians, for their Paschalia. Therefore, when the full moon occurs between March 21 and April 2 (New Style, of course) this is the Paschal moon only for the Western Church, since according to the Eastern Paschalia the vernal equinox has not yet occurred. In this case, the Orthodox Pascha is based on the following moon, a month later. This then would be the first full moon after March 21 according to the Old Style, but in fact it is really the second full moon following the astronomically actual vernal equinox (March 21 New Style).

In this case, the difference between the two Paschal dates can be four or five weeks. Should there be no full moon between March 21 and April 2 New Style, then for all Christians the common Paschal moon would be the first one occurring after April 2. In that case, both Paschal dates would coincide or be one week apart. The latter could occur because in the Paschalia lunar cycles  lag behind “real time” by three to four days. Thus if the actual full moon occurs in the first half of the week, for the Paschalia this would be in week’s second half and the following Sunday would be Pascha for all Christians. Should the full moon occur in the week’s second half, according to the Paschalia this would be the first half of the following week and thus the Eastern Pascha would fall behind the Western by a week.

There is only one solution for this abnormal situation. The feasts of the Paschal cycle must be observed in accordance with the same calendar as the fixed feasts (Christ’s Nativity, etc.), the calendar that corresponds to solar time.


“Russkaya Mysl’” #4401 21.03.2002

Translated by Alvian N. Smirensky

Last modified: April 22, 2002 - webmaster@holy-trinity.org.