Easter moves every year.
The Christian holiday of Easter celebrates the resurrection of Jesus Christ. The Bible says Jesus died on a Friday but rose again on the third day, a Sunday.
Those who agree that this is literally true acknowledge that the exact date of the death and resurrection are unknown. Of course, those who follow the Christian religion and also believe in the literal birth of Jesus don't know the specific date either. So why is it that Christmas, the celebration of Jesus' birth, is a fixed date on our calendar, but Easter seems to hop around the spring calendar like ... well, like an Easter bunny?
In the Bible, the birth of Jesus didn't occur around any specific Jewish holiday. His resurrection, however, occurred around the Jewish celebration of Passover. In the early centuries following Jesus' death, some Christians would celebrate his resurrection on Passover; some would celebrate a week later.
It wasn't until 325 that the Council of Nicaea took up the debate about the proper date to celebrate Easter. The council was convened by the Roman Emperor Constantine to settle issues that were dividing the church, the most important being the divinity of Christ. The Nicene Crede, a statement of faith still widely accepted and recited by Christians, came out of that council.
What the council didn't accomplish, however, was to create a fixed date for Easter. Instead, they came up with a way to determine a date for Easter each year that has confused many people since.
According to Time and Date, the council decided that Easter would be the first Sunday after the first full moon (modernly known as the Paschal Full Moon) after the vernal equinox — the day in the first half of the year when both day and night are exactly 12 hours long. On our modern calendar, it's the official first day of spring, which can fall on March 19, 20 or 21.
Easter can never happen before the vernal equinox, but it can happen on almost any Sunday after it up until April 25. This year, Easter will fall on April 21, 2019. If that seems much later than usual, there's a reason for that. In the last 365 years, the date for Easter has only been later than April 21 about 14 times, according to WLKY.
The only time Easter isn't on the Sunday after the full moon is when it would fall on the same day as the Jewish celebration of Passover. In that situation, Easter is celebrated the following Sunday.
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