Why is this feast celebrated on different dates? The explanation includes counting lunar months and calculating equinoxes
Last year, an early-April trip to Poland provided an interesting insight into the calendar system. Heavy snow still covered the streets and temperatures were unusually low, causing concerns about climate change and the well-being of the storks who had already returned, only to find frozen fields and lakes deprived of any food. In Poland, as well as in the Catholic and Protestant parts of the world, Easter had already been celebrated at the very end of March, and Easter bunnies made of snow were still sitting in the gardens of some creative people. We were kind of happy, as in 2013 the Bulgarian Easter was much later, in May.
The dates of Easter, however, are constantly changing. It is a pure coincidence that in 2014 Catholics, Protestants and Eastern Orthodox will all celebrate on the same day, 20 April.
The raising of Jesus Christ from the dead is central to Christianity, as it gives hopes to believers that they, too, will be resurrected on the Day of Last Judgement. But why does Easter moves all the time and why it is often on one date for Eastern Orthodox Christians and on a completely different date for Catholics and Protestants?
The reasons are difficult to understand and are almost as old as Christianity itself.
According to the Gospels, Christ was crucified the day before Passover and arose from the dead a day after it. Passover is a Jewish holiday which is celebrated from dusk on 14 Nisan until dusk on 15 Nisan, the Hebrew lunar month. The Hebrew calendar is based on lunar months calculated on the phases of the Moon. When used together with the solar calendar, which is calculated by the movement of the sun in the sky (think about equinoxes and solstices), the lunar dates appear to move back and forth. Passover is celebrated on the first full moon after the vernal equinox on 21 March.
Celebrations of Easter, however, do not coincide with celebrations of Passover – or at least most of the time. To make things even more complicated, they vary between the two main Christian denominations.
For 2000 years Christians have had different opinions on the date of the Resurrection. The problem came as early as the 2nd Century, when Christianity was in its infancy and the creation of a church hierarchy was in the making. Scattered around the Mediterranean Sea, Christian communities were a mixture of different and often contradictory beliefs, opinions and traditions. The nature of Christ was widely disputed (was He a God, a man or both?) and accusations of heresy were not uncommon.
With no binding authority, some of the communities celebrated the Resurrection on the same date as the Jewish Passover. Others pointed to a detail in the Gospel of Mark (16:9), reading that Jesus rose early on Sunday, and so they celebrated the event on the first Sunday after Passover.
There was some friction between these groups, but things continued undisturbed until Christianity was decriminalised by Emperor Constantine I, in 313. The new religion gained momentum – by the end of the century it would become the official state religion – and some clarification and unification was vital. In 325, Emperor Constantine presided over the First Council of Nicaea, which tried to tidy up the loose ends in Christianity. If you have read your Da Vinci Code carefully, you probably remember that this council chose which of the Gospels in circulation were canonical and which should be discarded as "unorthodox".
The Council did not overlook the Easter problem and decided that it should be celebrated on the first Sunday after the first full moon after the vernal equinox.
Yet, differences remained. The churches in the East were resolute that, in spite of astronomy and the actual vernal equinox, the Resurrection could not be celebrated before or during Hebrew Passover. If this were to happen, Easter would have to be moved on one lunar month.
The churches in the West, however, stuck to the pure astronomical logic and celebrated Easter whenever the calculations required.
In 1582, it became even more complicated, when Pope Gregory XIII changed the calendar.
The Old World had been calculating dates according to the Julian calendar since its introduction by Julius Caesar in 45 BC. It was the best that could be calculated at the time, but it was somewhat longer than the real astronomical year, so that three extra days accumulated every four centuries. Gradually, the dates started to differ from the astronomical equinoxes and solstices, and by the time of Pope Gregory XIII, the vernal equinox was not on 21 March, but on 11 March.
The calendar reform aimed to set things right and to bring Easter back to its original date.
The churches in the West were quick to adopt the new calendar, while the Eastern ones were not as enthusiastic. As a rule, the Eastern Orthodox denomination is more conservative regarding changes, especially when they emanate from Rome. Too much strife between the Christian churches followed the First Council of Nicaea in 325, including mutual accusations of heresy, power struggles and support for rival states.
East and West severed ties in what has gone down in history as the Great Schism of 1054, and the Crusades did not do anything to made things better. When, in 1453, the Ottomans tightened their grip over Constantinople, a Byzantine nobleman declined Western help, coining the now infamous: "Better the turban of the Turk than the tiara of the Pope!"
The calendar problem lingered on. It took literally centuries for the Eastern Orthodox nations to accept the Gregorian calendar for secular use. Bulgaria did this in 1916 and Greece was the last to follow suit, in 1923.
The Eastern Orthodox churches still use the Julian calendar for the movable feasts and have managed to turn the dates of the immovable feasts into yet another cause for dispute. The more conservative churches, including those in Russia, Serbia and Macedonia, apply the Julian calendar for both the movable and the immovable feasts. Those in Bulgaria and Greece have adopted the Gregorian calendar for immovable feasts like Christmas. They have made only one, small change – the renaming of the Gregorian calendar, now known as the Revised Julian calendar.
In recent years, there have been calls for the standardisation of the date of Easter. Some have proposed setting an immovable date in April, while others suggested another calculation reform. All efforts so far have failed. For now, the only possible joint celebration is in those years when the calculations of the East and the West coincide, as in 2014.
The next common Easter will be in 2017 – not a long wait, at least not in the universal scale of things.