I was asked by a friend to explain the difference in the date of Orthodox Pascha/Easter. Much of the article is a compilation of articles from Lewis Patsavos and Fr. Nabil Hanna. The date of Pascha has been controversial since the beginning of Christianity and early gave way to local customs. Some churches would celebrate on the actual Nisan 14, which was the actual date of the Resurrection, but it did not always fall on a Sunday. Other churches observed it on the Sunday following the Jewish Passover. By the 4th century, the latter practice prevailed throughout the Church; nevertheless, differences continued to exist.
In response to this ongoing problem, the First Ecumenical Council convened at
Another factor which figures prominently in determining the date of Pascha is the date of Passover. Originally, Passover was celebrated on the first full moon after the vernal equinox. Christians, therefore, celebrated Pascha according to the same calculation-that is, on the first Sunday after the first full moon following the vernal equinox. The correlation between the date of Pascha and the date of Passover is clear. Our Lord's death and resurrection coincided with Passover, thereby assuring a secure point of reference in time. This assurance lasted, however, only for a short time.
Events in Jewish history contributing to the dispersion of the Jews had as a consequence a departure from the way Passover was reckoned at the time of our Lord's death and resurrection. This caused the Passover to precede the vernal equinox in some years. It was, in fact, this anomaly which led to the condemnation reflected in Canon 1 of Antioch (ca. 330) and Canon 7 of the Holy Apostles (late 4th century) of those who celebrate Pascha "with the Jews." The purpose of this condemnation was to prevent Christians from taking into account the calculation of Passover in determining the date of Pascha.
Most Christians eventually ceased to regulate the observance of Pascha by the Jewish Passover. Their purpose, of course, was to preserve the original practice of celebrating Pascha following the vernal equinox, without having to rely on the local rabbi’s spotting of the new moon. Thus, the Council of Nicaea sought to link the principles for determining the date of Pascha to the norms for calculating Passover during our Lord's lifetime. They adopted, therefore, a solar calendar based upon the best scientific and astronomical data of the time. In fact they adopted the civil calendar of the
Despite the intervention of
A further cause for these differences was the adoption by the
Pope Gregory promulgated his new calendar in 1582. The motivation of the calendar was to create a more accurate reckoning of the Pascha date. Roman Catholic lands adopted it fairly quickly, but Protestant and Orthodox lands did not.
Practically speaking, this means that Orthodox Pascha may not be celebrated before April 3, which was March 21, the date of the vernal equinox, at the time of the First Ecumenical Council. In other words, a difference of 13 days exists between the accepted date for the vernal equinox then and now. Consequently, it is the combination of these variables which accounts for the different dates of Pascha observed by the Orthodox Church and other