According to scripture, Jesus rose from the dead on the first Sunday following Passover.
See Matthew 28:1, Mark 16:1-3, Luke 23:56-24:3, and John 20:1. For this reason, ancient
Christians celebrated Easter on the first Sunday after the Jewish Passover, which is
14 Nisan on the Jewish calendar. The only exceptions were in Syria and Mesopotamia,
where ancient Christians celebrated Easter on 14 Nisan, no matter which day of the week
it happened to be.

No one in ancient times denied that the Resurrection took place on a Sunday.

According to scripture, the month of Nisan—and therefore the date of Passover—is linked
to the spring harvest in Palestine. (See Exodus 12:1-3, Leviticus 23:9-14, and
Numbers 28:16.) However, the Romans banished all Jews from Palestine after the
rebellion of Simon Bar Kochba in AD 135, making it difficult for the rabbis to determine
the proper date for Passover. So sometime around AD 200, the rabbis reformed the Jewish
calendar. The new calendar unfortunately allowed Passover to precede the spring equinox
and it allowed two Passovers in the same twelve-month period. Obviously, the spring
harvest cannot precede the spring equinox and there should only be one Passover between
any two spring equinoxes. Shortly after AD 300, the rabbis revised the Jewish calendar
again to fix these problems.

By this time, the vast majority of Christians had long since given up using the Jewish
calendar to determine Easter. They celebrated Easter on the first Sunday after the first full
moon that followed the spring equinox, but since there was no standard way to calculate
the spring equinox, it was still possible for different regions to celebrate Easter on different
Sundays. The only serious hold-outs were, again,  the churches in Syria and Mesopotamia,
who continued to celebrate Easter on 14 Nisan, regardless of the day of the week. They
believed they had apostolic direction to celebrate Easter on the same day that the Jews
celebrate Passover, even if the Jews got the date wrong.

In AD 325, the Council of Nicea was convened to deal with Arianism and to standardize
the date of Easter. The Council of Nicea, noting that Syria and Mespotamia represented a
small minority, required them to conform to the practice of the majority. The bishops
from Syria and Mesopotamia agreed to this ruling and their churches complied with it. The
Council of Nicea also ruled that all churches must celebrate Easter on the same day. This
clearly implies that they instituted a standard method for calculating the date of the full
moon after the spring equinox, but the documentary evidence for it has not survived.
Some ancient writers, notably Ambrose, felt that the Council of Nicea prescribed the
mathematical formula that we presently use to fix the date of Easter, but we can no longer
prove it.

The Western Church applies the Nicene formula to the calendar as reformed by Pope
Gregory in 1582. (This calendar reform resulted in the Gregorian calendar that we use
today for secular purposes.) The Eastern Church applies the Nicene formula to the old
Julian Calendar, which was instituted by Julius Caesar and served as the civil calendar of
the Roman Empire before the birth of Christ. The Eastern Church also applies the
formula in such a way that Easter always falls after the Jewish Passover.

The important holy days during Easter are as follows:

     Easter Day
     Ascension Day, the fortieth day of Easter (Acts 1:11)
     Pentecost, the fiftieth day of Easter. For the eastern Church, Pentecost Sunday and
     Trinity Sunday are the same day.

Roughly speaking, the western Church consists of Protestants, Catholics, and Anglicans. The
eastern Church consists of the Orthodox churches and the eastern-rite churches affiliated with the
Roman Catholic Church.

Easter is an English word derives from the name of a Germanic goddess of fertility.
On the other hand, the Old Testament book of Esther is named after a Jewish heroine
who bore the name of the goddess Ishtar! In the ancient Church, the celebration of the
Resurrection was called Passover. Today, Orthodox Christians call this holiday Pascha,
(as in paschal lamb) which is the Greek word for Passover. In Anglican churches, the
designation Sunday of the Resurrection is often preferred over Easter and in Lutheran liturgy,
it is called The Resurrection of Our Lord.

The current ecumenical trend in English-speaking countries is to use Easter for the fifty-day
season and Easter Day for the day of the Resurrection.

Aside from English and German, the words for Passover and Easter are the same in most
languages.

The Nicene Creed is the definitive statement of Christian orthodoxy.

Origins of the Nicene Creed

The Nicene Creed was formulated at the First Ecumenical Council at Nicæa in AD 325 to
combat Arianism, and it was expanded at the Second Ecumenical Council at
Constantinople in AD 381 to balance its coverage of the Trinity by including the Holy
Spirit. It is the only creed that was promulgated by any of the seven ecumenical councils
and thus it is the only creed that is truly ecumenical and universal. In the Orthodox
Church, it is the only creed. The theology underlying the Nicene Creed governed the
Church’s recognition of the New Testament canon.

The filioque Clause

In AD 598, a church council in Toledo, Spain, modified the Nicene Creed so that the
Holy Spirit is said to proceed from the Father and the Son. (In Latin, and the Son is filioque,
so this is known as the filioque clause.) There may not have been any particular motive for this
change, because it looks like something a scribe would do to mend the text. The filioque clause
spread through the western part of the church. In 796, Paulinus of Aquileia defended the filioque
clause at the Synod of Friuli, which indicates that it was opposed, and after about 800 it crept into
the liturgy in the Frankish Empire. Some Frankish monks used the filioque clause in their monastery
in Jerusalem in 807, but eastern monks disputed it as improper. Because the Frankish monks were
from the west, the matter was escalated to the bishop of Rome (Pope Leo III). He approved of the
sentiment, but he opposed the change in the wording. Leo arranged for the creed in its original form
(without the filioque clause) to be engraved on silver tablets and he had them placed them at St.
Peter’s tomb. After the split between Rome and Constantinople, the filioque clause became
part of the Nicene Creed in the Roman Catholic Church.

Protestants inherited the filioque clause from the Roman Catholic Church, but the
Orthodox never accepted this change for scriptural, theological, and procedural reasons—it
violates Canon VII of the Third Ecumenical Council at Ephesus in AD 431, which made
the Nicene Creed unchangeable by local councils. After recent consultations with the
Orthodox, the US Episcopal Church agreed to drop the filioque clause from the Nicene
Creed in their next version of the Book of Common Prayer.

The Importance of the Nicene Creed Today

The Church formulated the Nicene Creed before it selected certain apostolic writings,
called them the New Testament, and declared them to be Holy Scripture. Another way of
looking at it is that God chose the people who were bound by the Nicene Creed to select
the contents of the New Testament, thereby endorsing the theology of the creed. The
Nicene Creed is therefore a reliable test of our interpretation of the New Testament. If we
are at variance with the Nicene Creed, we are in error. So whoever denies the Trinity must
also deny the New Testament, and whoever upholds the New Testament as Holy
Scripture must also affirm the Trinity.

In the beginning, the Church did not have a formal creed, nor did it have a formal
definition of what was in the New Testament. Then it formulated the Nicene Creed to
express its doctrines and to serve as a test of orthodox teaching. So for a while there was a
Church with the Nicene Creed but no New Testament. After that, the Church formally
defined which apostolic writings were Holy Scripture, and called them the New
Testament. Therefore, whoever attempts to reconstruct the ancient Church with a New
Testament but with no Nicene Creed is reconstructing an imaginary church that never
existed. This doesn’t mean their church is invalid, it just means that it isn’t a historic
reconstruction, because in any part of Church history in which there was a New
Testament, the Nicene Creed was the official expression of faith and the final test of
orthodoxy.

The Nicene Creed in Worship

Traditional liturgical worship always includes the Nicene Creed whenever there is
Communion. It is a corporate proclamation that corresponds to the Schema (“Hear, O
Israel, the Lord thy God is one”) in the synagogue liturgy.

In the Roman year 4677, which we call 46 BC, Julius Caesar standardized the civil calendar
of the Roman Empire so that it had twelve months with fixed lengths. He also introduced
the concept of the leap day, which adds a day to February every four years. The Roman
government used the Julian Calendar for official purposes during the events of the New
Testament, but the general population continued to use their own local calendars.

To avoid confusion, documents intended for wide distribution often dated events by
referring to the names of officials who were in office rather than by using a calendar date.
The New Testament reflects this practice. Eventually the Church had to devise a method
of determining the date of Easter that would work everywhere in the Roman Empire. It
used the Julian Calendar for this purpose, because even though people preferred to use
their local calendars, they could easily determine the date in the Julian Calendar no matter
where they were.

All Orthodox churches continue to use the Julian Calendar when they calculate the date
of Easter and holy days that are dependent on the date of Easter. Some Orthodox
churches still use the Julian Calendar for all holy days, such as the Orthodox Churches of
Jerusalem, Georgia, Russia, and Serbia. If you have been watching the news on television,
you may have noticed that Christmas was celebrated on 7 January in Serbia and Russia.
That is because the Serbian Orthodox Church and the Russian Orthodox Church use the
Julian Calendar for all holy days. Julian 25 December 1997 falls on Gregorian
7 January 1998.

In computer technology, the term julian date does not refer to the Julian Calendar. It is a
misnomer for a method of ignoring the months and numbering the days of the year
consecutively from 1 to 365 (or 366).

By the sixteenth century, it became obvious that the Julian Calendar was out of step with
the seasons, causing Easter to slip later and later in the year. In 1582, Pope Gregory revised
the Julian Calendar to fix this problem, and the result is the Gregorian Calendar that we all
use for civil purposes. The Western churches and the Orthodox Church of Finland use
the Gregorian Calendar to calculate all holy days. The Gregorian Calendar is identical to
the Julian Calendar, except for the following:

     Ten days were removed from October 1582. This put the equinoxes back on the
     proper dates.
     In century years not divisible by 400, February does not receive an extra day. Thus
     there was a 29 February 1900 in the Julian Calendar, but not in the Gregorian
     Calendar. This ensures that the Gregorian Calendar remains synchronized with the
     seasons for the next 10,000 years or so—without this change, Easter would fall in the
     summer time after the 100th century. However, this causes the difference between
     the calendars to increase with time. At present, the Julian Calendar is 13 days slow
     compared to the Gregorian Calendar.
     New Year’s Day was moved from mid March to1 January.

The British Empire—which at the time included what is now the United States—switched
to the Gregorian Calendar in September 1752. Ordinary folk were so confused by the
change that they staged demonstrations against it.