Easter’s fluctuating date annually is rooted in ancient lunar calendars and a desire by early Christians to maintain a historical connection to the Jewish feast of Passover.
Saint Alphonsus Catholic Church Pastor Adam Royal said historical and astronomical formulas determine when the holiday is observed. Royal said the Council of Nicaea established a specific calculation in the year 325 to ensure the celebration remained tied to the timeline of the original biblical events.
“For us, Christ is not a mythological figure,” Royal said. “He is truly God made man born in time and history. And so we like to connect things to actual historical events. And so having this date change throughout the year is just a reminder of, you know, God really did come in the flesh and walk among us.”
Royal said the formula dictates that Easter falls on the first Sunday after the first full moon following the spring equinox. The Council of Nicaea fixed the ecclesiastical spring equinox at March 21, and the full moon is determined by a set of precalculated tables rather than strict astronomical observations.
“Yeah, you know, at the end of the day we had to pick a time,” Royal said. “And we could have picked a fixed date, but we would have lost some of the symbolism. And so it’s important for us to all celebrate on the same day, which is why ultimately an ecumenical council made the decision is so that Christians worldwide could be united, right, at the time that they’re celebrating.”
Royal said the original events of the crucifixion and resurrection occurred around Passover, which was dictated by the cycles of the moon because the Jewish people utilized a lunar calendar.
“The only thing I would add is that I think there’s been a renewed momentum in recent years between East and West to maybe work towards a common date of Easter,” Royal said. “And that’s something we can hope for in the future one day that universally all Christians will once again be celebrating Easter on the exact same day. But it will take time and prayer to hopefully reach that point one day.”
Royal said Eastern and Western churches sometimes celebrate on different dates because the Eastern church continues to observe the Julian calendar. March 21 on the Julian calendar can fall on a different day than it does on the Gregorian calendar, causing the calculations to be slightly off between the two traditions.
“Just unity,” Royal said. “You know, Christ certainly prayed that we would all be united, be one in him. And, you know, through various historical things and poor choices at times, there has been division and we just hope for greater unity over time to be better witnesses to Christ in the world.”