The Original Idea
It began in the 6th century with a Scythian monk, Dionysius Exiguus, who resided in Italy. He first suggested in his Liber de Paschate ("Book of Easter") that we count the years starting from the time of Christ’s birth. Interestingly his system was not adopted until the 9th century.
Dating from the creation of Adam
Prior to that, people living in the Christian world counted years differently. They either counted according to the reign of the Roman emperor, or based on the biblically calculated time since Adam, known as Anno Mundi (AM). The AM system was derived from biblical passages. If you read Genesis 5 for example, you learn that Adam lived to be 930 years old. You will also see that Noah was 600 years old at the time of the flood. And he was born when his father Lamech was 182, which was 1056 years after Adam. Using genealogies and birth dates, as well as the reigns of kings, and the period of Jewish captivity, you can calculate how many years from the time Adam was created.
An interesting aspect of the AM calendar was that based on their calculations back at the time of Christ, they figured it was roughly 5,500 years since the creation of Adam, depending on who’s count you used. So this meant the world would come to an end around 500 AD. This was because of their interpretation of the Scripture which says a thousand years are as a day to God, and a day is as a thousand years. They also knew that God created the world in six days and rested on the seventh. So they believed that the seventh day (or seventh period of a thousand years) would begin immediately after the first six thousand years from the creation of Adam. The seventh millennium was considered by early Christians to be the “day of the Lord.”
Dating from the birth of Christ
Dionysius developed another calendar based on the historical information available to him at the time. He set the year 1 at Christ's incarnation. This is where the term Anno Domine comes from, which means "The Year of our Lord. These days we just abbreviate it as AD. In this calendar, everything before Christ is referred to as BC. An event that occurred one year before Christ was born was called 1 BC (there was no year “zero”). But he made a mistake when he determined the year of incarnation. He was about four years off. This mistake was discovered after he developed his new calendar, but he did not correct it. This error persisted when it was implemented 227 years later, and still remains to this day.
Based on well-documented historical events that occurred around the time of Christ’s birth, we can determine the year He was born with a fair degree of accuracy. We know that he was alive during the reign of Herod the Great, according to the biblical record. And we know that Herod was associated with people like his life-long friend, Mark Antony, who is a well-known and well-documented historical figure. Consequently the year of Herod’s death is fairly well established historically, especially in the works of the Jewish historian, Josephus. According to the Encyclopedia Britannica, “After an unsuccessful attempt at suicide, Herod died at Jericho at the end of March or beginning of April in 4 BC.”
Dating from the founding of Rome
At the time of Herod the Great, the year was sometimes counted from the day when the city of Rome was founded. So each year would be considered anno urbis conditae (this is Latin for "in the year of the founded city" and is abbreviated AUC).
Marcus Terentius Varro introduced this method in the 1st century BC. Each year of this system of dating began on Founder's Day, which was April 21. It was rarely used in either the Roman or the Julian calendar. The predominant method of recording the date of events in those days was simply to name the two consuls that held office in a particular year.
But later around AD 400, this AUC system was used by the Iberian historian, Orosius. Then around AD 600, Pope Boniface IV also used it, in addition to the Anno Domini era (he reckoned AD 607 at AUC 1360).
Putting it All Together
We know that Dionysius Exiguus reckoned Christ’s birth to have occurred in 754 AUC, making it equal to AD 1. However, as I already mentioned, Christ was born during the time of Herod the Great, who certainly died in 749 or 750 AUC. Therefore, we can prove that Christ's birth actually occurred no later than 750 AUC. Because of this mistake regarding the date of Christ's birth, our calendar is off by about four years. In other words, if Christ was born as late as 750 AUC that would place the Nativity shortly before the year 4 BC. That means that if the current year is 2010, then it is actually 2014 or so. Therefore, if you are all caught up in the hype about 2012, then you should understand that 2012 has already passed!
Now consider the six millenniums and how the early church believed that the seventh millennium would usher in the day of the Lord. In 1658 an Anglican archbishop named James Ussher, who lived in what is now Northern Ireland, calculated the chronology of the Old Testament. He reckoned the creation of Adam to have been in 4004 BC- exactly 4,000 years before the birth of Christ. This means the 6,000-year mark was reached in 1997. Everything after that is part of the seventh millennium since Adam. If you believe as the early Christians did that the seventh millennium will usher in the day of the Lord, then for those who are serving Jesus Christ, these are exciting days that we live in.
In John’s epistle, written during the first century, he said it was the last hour when he wrote: “Children, it is the last hour; and just as you heard that antichrist is coming, even now many antichrists have appeared; from this we know that it is the last hour.” (1Jo 2:18). So the last days really began during the first century AD. And if we were in the last hour then, we know for certain that we are now in the final minute before Christ’s return.
Finally, the signs of the times indicate very clearly that we are very close to the return of our Lord Jesus. As Jesus told us to do, "But when these things begin to take place, straighten up and lift up your heads, because your redemption is drawing near." (Luk 21:28). It's later than you think!!
Do you want to know Him?
If you want to know Jesus, you can. It all begins when you repent and believe in Him. Do you know what God's Word, the Bible says?
“Jesus came into Galilee, preaching the gospel of God, and saying, ‘The time is fulfilled, and the kingdom of God is at hand; repent and believe in the gospel.’” (Mar 1:14b-15). He preached that we must repent and believe.
Please see my explanation of this in my post called "Do You Want to Know Jesus?"
Len Lacroix is the founder of Doulos Missions International. He is based in Eastern Europe, where he is helping leaders to be more effective at making disciples who multiply, developing leaders who multiply, and planting churches that multiply. www.dmiworld.org.