Notes on the Christian Calendar

Q: What are the origin and the definitions for the time line abbreviations B.C. and A.D.?

A: All calendars have an arbitrary starting point. At the time Christ was born, the Jews, the Romans, and others all had calendars with differently numbered years which began in different seasons. For a number of centuries, no one gave much thought to a unified Christian calendar. Most of Christendom used the imperial years based upon the reigns of the Caesars.

Over five centuries passed after Jesus’ birth before a monk named Dionysius Exiguus, who was working to determine the date of Easter, decided that Christ had been born 525 years earlier. Like many new inventions, his system of dating took a while to catch on: In this case, 206 years passed before the scholar Bede chose it for his Ecclesiastical History of the English People. Bede chose the system because his English audience had no sense of the times of the Roman emperors and the various calendars in use in the British Isles all had conflicting dates. He also began the use of BC — more on this in a moment. Bede’s work spread to the court of emperor Charlemagne and slowly spread throughout western Europe.

This covers the origins, now we need the definitions. Some people think that AD means “after death” (as in the death of Christ). Actually, it’s a Latin abbreviation, standing for Anno Domini or “in the Year of the Lord.” Fully expressed, the phrase was Anno Domini Nostri Jesu Christi, “in the Year of Our Lord Jesus Christ.” For a while, the Latin abbreviation ACN (Ante Christum Natum, “before the birth of Christ”) was used. Soon, however, “before Christ,” or BC, became the popular expression.

Bede’s work also led to a strange quirk of the Christian calendar. Most systems count upward from their origin point. The backwards counting of the BC portion of our calendar reminds us how the eternal God intruded into ordinary time through the incarnation and birth of Jesus. It places God “right smack in the middle” of human history — just where He needs to be. This notion combined with a general anti-religious or anti-Christian thought from current scholars has led to alternate abbreviations that you might see in many sources. CE and BCE, “Common Era” and “Before Common Era,” were intended to remove perceived Christian bias from the calendar.

However, the year numbers are so ingrained that 2005 CE is the same as AD 2005 and 1000 BCE no different from 1000 BC. Yet with all this, students of the Bible and world history agree that Dionysius picked the wrong starting date! Not having the most accurate records at his disposal led him to set Jesus’ birth at least four years too late. According to our current reckoning Herod the Great, who ruled in Jerusalem when the Wise Men came to visit, died in 4 BC.

Q: Just a short question: It has been bugging me since I thought of it, but why does Good Friday always land on a Friday? Christmas falls on different days of the week, so why does Good Friday always land on a Friday?

A: Unlike Christmas, which comes on a set date, Easter’s date can move from 22 March through 25 April in Western Christianity (and on still different dates in other parts of the world). Since Christ’s resurrection is intimately connected with the Hebrew Passover, the early Church used a lunar calendar as its starting point. And since Christ rose on a Sunday, it determined that a Sunday would always be the day of Easter’s celebration. After many years of discussion, the date of the Feast was settled: It would always be observed on the Sunday after the first full moon on or after the day of the vernal equinox (first day of spring). Because the Eastern (Orthodox) Church uses a different calendar, its date for Easter seldom coincides with the Western (Roman Catholic, Lutheran, Protestant) observation.

How does this tie to Good Friday? Since Christ rose “on the third day in accordance with the Scriptures (1 Cor 15:4)” we remember his death on the Friday preceding Easter Sunday.

Scripture quoted from The Holy Bible, English Standard Version™, © 2001 by Crossway Bibles.

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Walter Snyder is the pastor of Holy Cross Lutheran Church, Emma, Missouri and coauthor of the book What Do Lutherans Believe.