Why is Easter on a Sunday?

The first day of the week

The Jewish week had seven days, and only one had a name: the Sabbath, the seventh day, from Friday sunset to Saturday sunset (Exodus 20:8–11). The others were simply numbered. So the Gospels date the empty tomb by its number.

But on the first day of the week, at early dawn, they and some others came to the tomb, bringing the spices which they had prepared.

Jesus had died on a Friday, “the day before the Sabbath” (Mark 15:42), and was buried in a hurry before sunset. The women rested “according to the commandment” (Luke 23:56) and came back at first light on Sunday. Mark, Matthew and John use the same phrase (Mark 16:2; Matthew 28:1; John 20:1). In Greek it is mia tōn sabbatōn, day one counted from the Sabbath. Paul’s “raised on the third day” (1 Corinthians 15:4) counts the ancient way, both ends included: Friday, Saturday, Sunday. When exactly Jesus died is its own question: see the debate about the day he died.

A weekly Easter

The first Christians did not wait a year to remember it. They met on that day every week. At Troas, “on the first day of the week, when the disciples were gathered together to break bread,” Paul talked until midnight, so long that a young man named Eutychus fell asleep and fell out of a window (Acts 20:7–9). Paul tells the Corinthians to set money aside “on the first day of every week” (1 Corinthians 16:2). By the end of the century the day had a Christian name: John says he was “in the Spirit on the Lord’s day” (Revelation 1:10).

Outsiders noticed. Around 112, Pliny, a Roman governor, reported that Christians met on a fixed day before dawn to sing to Christ as to a god (Letters 10.96). Around 155, Justin Martyr explained to the emperor that Christians gather on Sunday because it is the first day, when God made light out of darkness, and the day Jesus rose (First Apology 67). Every Sunday was a small Easter.

How Sunday got its name

The Romans had taken up a seven-day week named for the planets, and the day after Saturn’s day belonged to the Sun. Christians kept the week but renamed the day dies Dominica, the Lord’s day, which gives Spanish and Portuguese domingo, French dimanche and Italian domenica. English kept the old name. In 321 the emperor Constantine made the day of the Sun a legal day of rest, as told in Who was Constantine the Great?

One Sunday a year

The yearly date took longer to settle. Churches in Asia Minor kept Easter on the 14th of Nisan, the date of Passover, whatever the weekday; Rome and most other churches kept it on the Sunday after. Around 190, Bishop Victor of Rome tried to cut the Asian churches off, Polycrates of Ephesus defended his custom as the apostle John’s, and Irenaeus begged for peace (Eusebius, Church History 5.23–25). In 325 the Council of Nicaea asked every church to keep one common day, independent of the Jewish calendar, and Sunday won.

Western churches now keep Easter on the first Sunday after the first full moon on or after March 21, so it falls between March 22 and April 25. Orthodox churches apply the same rule on the Julian calendar, so their Easter often comes later. Either way, it is a Sunday.