How the date of Easter is determined

Last week, we celebrated Mardi Gras, better known as Fat Tuesday — the beginning of the season of Lent.

In 40 days, we’ll celebrate Easter — the resurrection of Jesus Christ which changed everything, including the calendar.

Even in cultures around the world that either don’t know about Christianity or choose another religion, their calendar is still moving in the time of Anno Domini — in the Year of Our Lord. That is an amazing fact that the birth of Jesus is memorialized to this day by our very calendar! People who do not even know Him are still counting their days with a Gregorian calendar dedicated to Him.

Easter marks the end of Lent, the 40 days of fasting and abstinence that began with Fat Tuesday and Ash Wednesday. Easter is a moveable feast, meaning it is not fixed in relation to the regular calendar. It always occurs during the spring in March or April.

Easter is linked to the Jewish Passover by much of its symbolism as well as by its position in the calendar. Passover and Easter are interchangeable terms in many European languages, so the similarities are even greater for the early Christians who translated the Bible.

Secular customs, such as the Easter Bunny and Easter egg hunts, have become part of the holiday’s modern celebrations and are often observed by Christians and non-Christians alike.

The New Testament teaches the resurrection of Jesus, which Easter celebrates, is a foundation of the Christian faith. The resurrection established Jesus as the true Son of God.

Easter is strongly connected to the Passover and Exodus from Egypt outlined in great detail in the Old Testament.

In the New Testament, however, Jesus gave the Passover meal a new meaning. He said to his disciples, “Do this in remembrance of me,” as he prepared himself and his disciples for his death in the upper room during the Last Supper. He took the bread and the chalice of wine and said that it represented His body and blood.

Jesus, as the Passover lamb, was crucified at roughly the same time as the Passover lambs were being slain in the temple. To this day, on Good Friday at 3 p.m. is traditionally the time observed.

Every Friday during Lent, many Christians observe the Stations of the Cross — 14 points on the Via Dolorosa in Jerusalem from the Lions’ Gate to the Church of the Holy Sepulcher. This is one of the most powerful Lenten traditions, even more so than fasting and abstinence.

Speaking of fasting and abstaining, it is also a longstanding tradition to fast (eat one meal a day or none at all) and abstain from meat on Fridays of Lent. This has led to many restaurants having fish and seafood specials on Friday nights.

Why is Easter on a moveable date? It’s determined on a lunisolar calendar similar to the Hebrew calendar. The First Council of Nicaea — the same council that wrote the Creed (“We believe in One God”) — established the date of Easter as the first Sunday after the full moon (the Paschal Full Moon) following the Northern Hemisphere’s vernal equinox way back in the year 325.

The equinox occurs on March 21; therefore Easter always falls on a Sunday between March 22 and April 25. There are 35 potential Easter dates.

It last fell on March 22 in 1818 and will not do so again until 2285. It fell on March 23 in 2008, but will not do so again until 2160. Easter last fell on the latest possible date, April 25, in 1943 and will next fall on that date in 2038. However, it fell on April 24, just one day before this latest possible date, in 2011. The most common date is April 19. This year, we’ll celebrate Easter on April 21.