MINNEAPOLIS (WCCO) — Easter is the celebration of the resurrection of Jesus Christ, but it falls on a different date every year.

This year the date is March 31. Last year it was April 8, and next year it’s slated for April 20.

The different dates got Joe Kummer from Hastings, Minn., wondering: How is the date of Easter determined?

Parents at the Mall of America bringing their children to see the East Bunny had a tough time answering the question.

One woman said, “Christmas can be on the same day, I don’t know how this changes.”

Father Mike Joncas with the University of St. Thomas has his doctorate in liturgical studies.

He calls this question complicated.

“Easter is celebrated on the first Sunday after the first full moon after the vernal of springtime equinox,” he said.

In astronomical terms, the spring equinox is March 21, so Easter can fall anywhere from March 22 to April 25.

Back in the 325 A.D., the First Council of Nicaea convened by the Roman Emperor Constantine determined the date. The significance of the full moon is because that was Passover in the Jewish calendar, when Jesus is believed to have celebrated his Last Supper. It’s always on a Sunday, because that was the day of the Resurrection.

The holiday is absolutely foundational in Christianity because it shows the new possibility of life beyond death and that’s open to everyone, Joncas says.

“Christians spent about 300 years trying to figure out when they would celebrate it liturgically,” he said.

So, how is the resurrection of Jesus Christ associated with the East Bunny?

“Well, that actually is the complexity of culture,” Joncas said.

The word Easter isn’t in any scripture. Back in the Middle Ages, people in the Northern Hemisphere associated this time of year with new life, or spring. Eostre is goddess in Germanic paganism, and fertile rabbits (or hares) are synonymous with new life.

But Joncas says Easter eggs do have a Christian connection.

The egg was the thing that cracks, and the new life, the chick that comes out of it, was seen by Christians as sign of the tomb breaking open and Christ coming forth, he said.

Early Christians in Mesopotamia used to dye the eggs red to signify the blood of Christ.

But, as far as the chocolate Easter bunnies are concerned, Joncas said he hasn’t a clue about those.

“I suspect that has less to do with life and more to do with useless calories,” he said.