For nearly a millennium, the Greek Orthodox Patriarchate of Constantinople and the Vatican have been engaged in what may be the longest-running ecumenical argument in history. A significant aspect of this divide is the calendar dispute—the Orthodox Church adheres to the Julian calendar, while Western Christianity follows the Gregorian calendar. This disagreement has turned time itself into a theological hot potato.
The feast of Easter, for one, a holy day timed to the spring equinox, has stayed in sync with the Gregorian calendar but not with the Julian calendar—a problematic time-reckoning inherited from the Roman Empire. That calendar, though representing tradition and identity and linking to Orthodoxy’s origins in the ancient world, has simply not behaved itself. So, while Western Easter rang in on March 31, Orthodox Easter didn’t happen until over a month later, on May 5.
However, with the potential decision by the Ecumenical Patriarchate of Constantinople, Bartholomew I, it could be the last time Cinco de Mayo coincides with Easter and the final time East and West fail to celebrate Easter on the same Sunday. If the Patriarchate embraces the Western Gregorian calendar, it will mark a monumental step towards healing a millennium-long divide between the two halves of Christianity.
It’s not as though attempts at reconciliation have never been made. The deficiencies of the Julian calendar became apparent to theologians and scientists alike in the early Middle Ages. Adding a day to the calendar once every 128 years was no solution, nor was the Great Schism of 1054, which severed Roman and Byzantine Christianity over matters of politics, power and practice. Nearly three centuries later, in 1326, the Byzantine astronomer and theologian Nicephorus Gregoras proposed a new calendar to fix the old. Byzantine emperor Andronikos II Palaiologos—already dealing with recently sacked-by-crusaders-Constantinople and fearing further conflict over a new calendar—vetoed the plan.
Over the ensuing centuries, the “It’s Complicated” relationship button between the two denominations was continually lit. The Protestant Reformation, sparked by Martin Luther, splintered Christianity yet again, so once calendar reform did take place—this time instigated by the Vatican with the Gregorian calendar in 1582—it took nearly two centuries and the fading of European holy wars for Protestant countries to come around to the change. But the Orthodox Church remained adamant in its adherence to the Julian calendar.
However, the twentieth century brought tectonic shifts in Eastern Europe’s political and, therefore, religious landscape. The Ottoman Empire collapsed, as did Imperial Russia. New states with civil rather than religious governing bodies adopted the Gregorian calendar over the stubborn refusal of Orthodox authority to change.
Then, in 1923, a Serbian scientist devised a compromise Revised Julian calendar. It had the convenience, he asserted, of being more accurate than both the Gregorian and Julian calendars, plus the bonus of lining up precisely with the Gregorian calendar for the ensuing 877 years. Therefore, the Orthodox Church could accept it and the more equinox-friendly Easter dates it offered while not appearing to be subservient to the pope in Rome.
On paper, it looked fine, but in reality, it caused more mischief. Many Orthodox churches, including the powerful Russian Orthodox Church, refused the change, while those churches that accepted it saw many factions splinter off over what they deemed heresy. Ultimately, a compromise stipulated that Easter would remain the “Old Calendar” Easter throughout the Orthodox world, regardless of their marking system.
And so it has remained to this day, with only the Orthodox Church of Finland adopting the Gregorian calendar and the Gregorian Easter.
Both East and West ecumenical leaders expressed hope for a commonly agreed-upon date for Easter. Patriarch Bartholomew I, while sending “a heartfelt greeting of love” this March 31 to all Christians celebrating Easter on that day, also said, “It is a scandal to celebrate separately the unique event of the one resurrection of the one Lord.” He prayed that next year’s Easter would happen on the same date for all Christendom.
Similarly, Pope Francis commented on the illogic of disunity on the date of Easter, joking that Christians could say to one another: “When did Christ rise from the dead? My Christ rose today, and yours next week.”
Easter 2025 will be particularly significant, marking the 1,700th anniversary of the First Council of Nicaea in 325, when both Eastern and Western Christianity were in full harmony. “Among [the Council of Nicaea’s] pivotal discussions was the matter of establishing a common time frame for the Easter festivities,” Bartholomew said. “We are optimistic, as there is goodwill and willingness on both sides.”
Photo credits: Design drawing for stained glass window of Resurrection. Library of Congress.