Updated: Nov 8, 2019
Rome had something called the Roman Calendar. The Romans began their chronology with the year of the founding of pagan Rome which compared to the Christian Calendar (our calendar) would be about 753 B.C. It was a big old mess originally dividing the year into 10 months which left 60 days unaccounted for. Early on they tried to fix it by adding the months of January and February to the end of the year to keep the calendar in line with the solar year. They would add a month when necessary, at the discretion of the pontifex maximus. (The pontifex maximus was the high priest of the ancient Roman religion.)
Unfortunately the pontifices often adjusted the Roman Calendar to lengthen or shorten an official’s term or to manipulate elections. Julias Caesar (100 B.C. – 44 B.C.) realized the need to end the abuses and saw the need for using a uniform and consistent calendar throughout the Roman Empire. In 45 B.C. he asked Greek astronomer Sosigenes of Alexandria to come up with this new calendar. This calendar was called the Julian Calendar. It had to do with the length of the year not the actual year, but it had issues though too. Its year was 11 minutes and 14 seconds longer than the actual solar year. After Caesar’s death in 44 B.C., the seventh month of the calendar was renamed to July in his honor.
Roman Emperor Constantine the Great decriminalized Christianity in the year A.D. 313. Constantine became the first Christian Roman Emperor. It was this period in history when the Roman Empire went from pagan worship to Christianity.
When Easter fell was a big old debate. In A.D. 525 Pope John the First asked a monk named Dionysius Exiguus (Dionysius the Little) to come up with tables for determining the date of Easter. While working on this, Dionysius decided to abandon the pagan way of numbering years and base the division of time on his calculated year of the birth of Jesus Christ. He used a combination of biblical references and other data to come up with the year Jesus was born. Luke 3:1,2 tells us Jesus was baptized in the 15th year of the reign of Tiberius Caesar, when Pontius Pilate was governor of Judea, and Herod was tetarch of Galilee, and his brother Philip was tetrarch of the region of Ituraea and Trachonitis, and Lysanias was tetrarch of Abilene, in the high priesthood of Anna and Caiaphas,... And in Luke 3:23 we are told that Jesus was about 30 years of age at the start of His ministry (His baptism.)
Dionysius calculated Jesus was probably born in the 753rd year since the founding of the Roman empire. He suggested dates should be given the initials A.D., standing for Anno Domini meaning “in the year of our Lord” and earlier dates referred to by B.C., Before Christ. However, A.D. and B.C. weren't formally adopted until Charlemagne did so in A.D. 800. The calendar in use was still the Julian Calendar which was still off by those 11 minutes and 14 seconds. So adjustments kept having to be made to the calendar. Dionysius' work only affected how the years are counted. It didn't fix the annual calendar.
The day Easter was celebrated kept being moved out of the traditional season. Pope Gregory XIII said enough and decreed in A.D. 1582 that ten days should be dropped from that year! People were none too happy! The Gregorian Calendar, also called the Christian Calendar, was developed and was immediately adopted in most Catholic countries, including Spain, Portugal, and parts of Italy. Protestant countries accepted it somewhat later. It was introduced into Scotland in 1600. Great Britain and the American Colonies adopted it in 1752. Russia and other Eastern Orthodox countries did not accept the Gregorian Calendar until after World War I!
Anyways, poor Dionysius got the year of Jesus’ birth wrong! He missed the date by 4 or 5 years. Matthew 2:16 tells us that Herod had all of the male babies from two years old and under in Bethlehem killed. Herod was trying to have Jesus, the King of the Jews, killed. (By the way there are 7 Herods mentioned in the Bible.) Dionysius calculated the year he thought Jesus was born based on the biblical and other information he had in A.D. 525. Josephus, a first-century Jewish historian, tells that Herod died shortly after an eclipse of the moon, but prior to Passover. Astronomers today know there were 3 eclipses of the moon in that time period. On this and other evidence, historians determined King Herod died in 4 B.C. King Herod ordered the slaughter of the infants two years old and under in Bethlehem. Jesus had to be born before Herod died in 4 B.C.
This evidence leads historians to believe Jesus was born around 5 B.C.! All of my reference books list Jesus’ birth somewhere between 6 B.C. to 4 B.C. We know Jesus was about 30 when He began His ministry. We know He ministered about 3-1/2 years. So Jesus would have been crucified around A.D. 27-30.
So what year is it really right now? Well it is really around 5 years ago! We get a do-over, ha ha. Pretty fascinating, huh?
About this point you are wondering why I was so geeky to research this. Many years ago I was in a class called Bible Basics and one of the guys asked the teacher what year was Jesus born A.D. 0 or 1. The teacher didn't have a clue. Then when I took a class on the New Testament and the teacher put up a slide of the timeline of when they think the books of the New Testament were written; it had Jesus was born in 5 B.C. I asked about it. She told us a little about Dionysius. Later I developed a class on The New Testament Historical Books (Matthew through Acts) and I researched it more to be able to adequately answer the students if they ask. Plus I just found it interesting.
What does it have to do with encouraging you to read the Bible? Not a whole lot except to let you know that back when the books of the Bible were authored and passed on, the calendar as we know it didn't exist. So the authors referred to historical events to measure time - often by referring to the reign of a certain ruler. For instance 1 Kings 15:28 says: So Baasha killed him in the third year of Asa king of Judah and reigned in his place.
Does it really matter if we know the exact year Jesus was born? No.
It only matters our Savior was born!
Happy New Year!