By now it’s likely you’ve realised that Greek Easter doesn’t usually fall on the same day as everyone else’s.
This year Orthodox Easter falls on 1 May while every other Christian is celebrating Easter tomorrow, and there’s a good reason for that.
The Orthodox Christian Church calculates the date of Easter differently to other Christian denominations; it’s not merely done to confuse everyone. But every now and then, the two methods result in both Easters falling on the same date.
In the case of the Greek Church, they go by the Julian calendar, rather than the Gregorian calendar. This is the calendar that was officially implemented by Julius Caesar and was in use primarily between 45BC and AD1582, and was therefore used when the Orthodox Church was initially set up. Though much of the world now uses the Gregorian calendar, which replaced the Julian calendar, the custom has remained to use it to calculate the date of Easter, which is one of the reasons why Orthodox Easter often falls on a different date.
After the 40 days of Lent, Orthodox Christians celebrate Holy Week, which begins on Palm Sunday. When Jesus first arrived in Jerusalem, he was hailed as a king, and this is the occasion honoured during Palm Sunday. As the events of Holy Week unfold, Orthodox Christians commemorate the events that led up to his arrest, execution, and then his resurrection.
In the Bible, all of these events took place after Passover. There is some debate among scholars as to whether or not the Last Supper was actually a Passover meal. However, in the Orthodox Church, it is acknowledged that Jesus and his disciples shared this Passover meal together.
Through this meal, Jesus established the Holy Eucharist, thus transforming the custom from a Jewish one to a Christian one. As you may recall, this meal happened shortly before Jesus was arrested. Judas sat at that supper table knowing that he had betrayed Jesus and that his arrest was inevitable.
Note that Passover falls at a different time each year, which is another reason why the date for Easter varies.
Another important element to calculating Greek Easter is the autumn equinox. Generally, the date for Easter is set on the first full moon after both the autumn equinox and Passover. Each year, the date of the autumn equinox in the Julian calendar is slightly different, usually falling somewhere in the third week of March. However, since it differs each year, it can also affect when Greek Easter falls.
With all this in mind, it’s easy to see why calculating the date of Greek Easter can be a difficult task and is the main reason why Eastern and Western Easter often fall on different days.
Once every few years, however, the days coincide, but this is the exception and not the rule.
Source: GreekBoston.com