When were AD and BC decided? AD probably started in AD 525 and BC probably started in AD 731. All of these are “probably” because there is no concrete evidence.
AD is an abbreviation for anno Domini Nostri Jesu Christi, and means “in the year of our Lord Jesus Christ”. BC stands for Before Christ. AD is a Latin abbreviation and BC is an English abbreviation because of when they were created.
Throughout most of recorded history, until the early Middle Ages, years were generally recorded by the king that ruled during them. This meant that calendars across the world would vary from civilization to civilization and there was no standardized system. The Egyptian calendar was recorded by the pharaoh that ruled and a list of all pharaohs was kept. The Roman calendar was recorded by the consul that ruled and then by the emperor that ruled. When this became too confusing, they started to calculate it by how many years had passed since the founding of Rome. Most civilizations that kept a record did so by using their kings as markers. That may seem odd to us, but there was no need to standardize things and there was no need to keep an exact record of things. Instant, global communication was obviously not possible and there was no need to standardize dates and years around the world, at least until Europe started to colonize the world.
AD came about because a Christian monk called Dionysius Exiguus was tasked with calculating when Easter was. Easter was a very confusing time and the date had to be calculated using different calendars that sometimes conflicted with each other. The church, if it was the mouthpiece of the Lord, had to know when Easter was, so tables were calculated and published by the Pope. While calculating his Easter tables, Dionysius also came up with the AD system. He lived from 470 to 544 AD, although he wouldn’t have known that until the end of his life. He moved to Rome when he was about 30 and he was a translator of religious texts. He became renowned for his knowledge, and he put a lot of work into the Easter problem. Because he lived in Rome, he lived under the Roman system of dating and it was currently using a system called the Diocletian system, which counted the number of years since Emperor Diocletian became emperor. Diocletian had been a tyrant who had removed the rights of Christians, destroyed their churches, and persecuted them. Dionysius didn’t want to link his Easter calculations to the Diocletian system of years, so he decided to base it on the birth of Jesus Christ, which would be far more fitting for Christians. There is no evidence of how he calculated when Jesus was born, but he would have undoubtedly tried to connect accounts in the bible with historical events. He knew Jesus was born during the reign of Herod, and he would have had dates for that. There are a few other pieces of information that he would have used and he calculated that the year Anno Diocletiani 247 was 531 years after the birth of Christ. Therefore, the first year in his table came the next year and he called it Anno Domini 532. Modern historical researchers have a lot more information to go on than Dionysius did and modern evaluation shows that Jesus was probably born about 4 years earlier, in 4 BC.
His new system was slowly picked up by writers and historians of the centuries after him. Bede, an Anglo-Saxon historian used the expression AD. By the 9th century it was common across the Christian world. It didn’t become common around the whole world until Europe embarked on its era of colonization.
BC came around a little later. Again, there was not a great need to have dates for all of history until fairly recently. The study of ancient history and archeology really took off in the late 18th century and early 19th century. The Industrial Revolution brought increased wealth and increased education with it. There was a sudden desire to know more about the past. Archaeology, paleontology, the study of ancient man, and classical history all seem to start in this period. The AD dating system had become common, so a way of dating before that became necessary. This was BC and the historian Bede was the first person to suggest it. In his “Ecclesiastical History of the English People” in 731, he wrote about years “before the birth of Jesus Christ”. He called them “ante incartonionis dominicae tempus”, which means “before the time of the incarnation of the Lord”. This is shortened to AC in many languages. In English it is BC. Bede counted backwards from 1 BC, so the numbers go up as we go further back in time. He also started at 1, rather than 0 because the number 0 wasn’t known about in Europe until 1200.
The BC AD system became more common in the later Middle Ages. The Emperor Charlemagne used it for dating acts of government. Then when the Gregorian calendar was introduced in 1582, it was permanently set in place as European colonialism carried it around the world. It was set as the standard system in 1988. However, recently, there has been call for a system that isn’t based on a single religion, or on religion at all. This system uses CE (common era) and BCE (before the common era). And this is what I learned today.
Photo by Navneet Shanu: https://www.pexels.com/photo/brown-carriage-wheel-672630/
Sources
https://en.wikipedia.org/wiki/Anno_Domini
https://www.livescience.com/45510-anno-domini.html
https://www.livescience.com/45768-gregorian-calendar.html
https://time.com/4462775/bc-ad-dating-history/
https://en.wikipedia.org/wiki/Diocletianic_Persecution
https://en.wikipedia.org/wiki/Dionysius_Exiguus
https://www.theguardian.com/notesandqueries/query/0,5753,-14860,00…
https://byustudies.byu.edu/further-study-chart/8-4-dating-the-birth-of-christ/