Living in a non-Orthodox country we Orthodox are frequently asked why we celebrate Eastern on a different date in regards to the Western Christians. This also creates issues in respect to schools and work, when the faithful are unable to go to all or most of the services during Holy Week because Eastern is either 2 or 5 weeks after ‘normal’ Easter. Nevertheless, the issue relies on the complicated nature of calendars and the way with which astronomical data is used.
The dating of Easter, of the death and resurrection of Jesus, has always presented variations within the Church. Even within the Bible we observe two distinct traditions. In the first instance the traditions of the three Synoptic Gospels, i.e. Matthew, Mark and Luke, identify the Last Supper as being a Passover meal. Therefore, Christ was crucified the day after Passover. In the second case, the Gospel of John states that the crucifixion took place the same day as the Passover. Hence, these two traditions led to the establishment of two distinct practices. The first opinion established the celebration of Easter on a set date, despite the day, whilst the second one fixed it on the Sunday after Passover. Nevertheless, by the fourth century the latter practice prevailed, with differences within the Catholic Church.
A decision had to be taken, not only from one part of the Church, but by the whole Body of the Ecclesia. This issue was addressed during the First Ecumenical Council at Nicaea (325 AD). During this Synod it was decided that Easter is to be celebrated on the Sunday that follows the first full moon after the vernal equinox, which is when spring starts. If, on the other hand, the full moon falls on a Sunday, then Pascha is celebrated the following Sunday. The day taken to be the invariable date of the vernal equinox is March 21st.
Another factor, on which the dating of Easter is based on, is the date of the Jewish Passover. Due to certain historical changes within the Jewish world, Passover was calculated differently, i.e. meaning that Passover in some years preceded the vernal equinox. The two celebrations of both religions coincided; however, this existed for a short period of time. In Canon 1 of Antioch (330 AD) and Canon 7 of the Holy Apostles (4th century AD) condemned the calculation of Easter according to the Passover. However, the First Ecumenical Council endeavoured to maintain the calculating of Passover according to Jesus’ lifetime.
Until the 6th century variations on the calculation of Easter were still apparent. Nevertheless, a more secure mode of calculating, based on astronomical date, was accepted by the Catholic Church. This was an alternative to calculating Eastern by the Passover, forming the so called “paschal cycles”. Each paschal cycle matched to a number of years. According to the number of years in the cycle, the full moon occurred on the same day of the year as at the start of the cycle, with of course some exceptions. The more accurate the cycle, the less frequent were the exceptions. In the East part of Christendom a 19 year cycle was eventually adopted, whilst on the Western part an 84 year cycle. Therefore, due to this difference, we observe that East and West celebrate Easter on different dates.
Another factor which contributed towards the widening of this difference was the adoption, by the West, of the Gregorian Calendar (1582), thus replacing the Julian Calendar. The Orthodox Church bases the calculation of Easter on the Julian Calendar, the calendar used by the ancient Church.
Could this change? Open minded leaders will be able to answer this, theoretically but also practically. It has been an issue, in regards to the on-going Ecumenical Dialogue. The celebration of Easter on the same date within the whole Christian family, worldwide, would be an important step within the Ecumenical Movement, showing a sense of love and understanding. With patience all could happen in the future.