The current year is 2012. How many years has it been since the Birth of Christ? The current calendar system counts the years as if Christ were born in 1 BC. But many scholars (not all) think that 1 BC is too late a date for the birth of Christ. How did our current calendar system come to place Christ’s birth in 1 BC?

Dionysius Exiguus was a Roman Catholic abbot and a theologian, with expertise in astronomy and mathematics. He devised the A.D. system of numbering the years according to the life of Christ.

In 525 A.D., Pope St. John I, asked a Roman Catholic abbot named Dionysius Exiguus to determine the dates of Easter for future years. Dionysius was a well-known theologian, who also excelled at mathematics and astronomy. The date for Easter is determined by astronomy. In determining these dates, Dionysius objected to the then-current system of numbering the years from the time of the emperor Diocletian, (third century A.D.), under whose reign there was a great persecution of Christians. Instead, he devised a calendar system where the years are numbered according to the Incarnation of Jesus Christ, ab incarnatione Domini (‘from the Incarnation of the Lord’). Today, we use the abbreviation “A.D.,” which stands for Anno Domini (‘in the year of the Lord’), but the numbering of the years is according to Dionysius.

Dionysius numbered the first full year after the Incarnation and Birth of Christ as A.D. 1. Thus, in A.D. 1, according to Dionysius, Christ would have completed one year of life since the Incarnation (early in the calendar year), and one year of life since His Holy Birth (late in the calendar year). The number of the year should reflect the age of Christ in this system. The custom of referring to the years before A.D. 1 as “B.C.” (‘before Christ’) did not develop until a later time. However, Dionysius did believe that Christ was born in the year before A.D. 1, which we now call 1 B.C.

Even though this new system of numbering the years was accepted by the Church, and by much of society, there is today no agreement among historians, Biblical scholars, theologians, or Church leaders that Dionysius chose the correct year to call A.D. 1. In other words, there is no general agreement that Christ was born in 1 B.C. It is not the official teaching of the Catholic Church, nor of any other Christian Church of which I am aware, that Jesus Christ was necessarily born in 1 B.C., as was the opinion of Dionysius.

Some Biblical chronologists believe that Jesus was born in 1 B.C. But most place our Lord’s birth some number of years earlier, anywhere from 15 B.C. (my date) to 12 B.C. (Vardaman and Kokkinos) to various years from 8 B.C. to 2 B.C. (several authors).

About this time of year, a number of posts and articles pop-up on the internet presenting one or another exceedingly over-simplified explanation of when Christ was born. But in fact, Biblical chronologists do not agree on the year of Christ’s birth. And any viable theory as to when Christ was born must take account of a great deal of information from a wide range of sources.

See my book Important Dates in the Lives of Jesus and Mary for my explanation as to when Christ was born, when He died and rose, and when other related events occurred.

by
Ronald L. Conte Jr.
Roman Catholic theologian and
translator of the Catholic Public Domain Version of the Bible.