Why are years based on Jesus? A history lesson

This morning I got an email from a guy named Scott, who asked:
Please answer the following:
If there is no God/Jesus, how are the years calculated? (ie: it is currently 2014)
I thought it would be easy to find a concise answer to this, but it turns out I had a bit of a hard time. So I’m showing my work! You’re welcome.
Hi Scott,
I can’t tell if you are kidding or not, but I can answer your question.
While atheists do not believe in God, or in the divinity of Jesus, we definitely believe that the human institutions of religion exist. The calendar that we use today in Western countries is called the Gregorian calendar. It was standardized in 1582; however, it was an adjustment to the older Julian calendar, so named because it was created officially instituted by Julius Caesar in 46 BC. Under this system, there was initially no year 1, as they measured time based on “epochs,” which were continually renumbered based on significant historical events.
In the year that later became 525 AD of the Julian Calendar, a Christian monk in Romania named Dionysius Exiguus invented the concept of the Anno Domini era. Under this new system, the years in the Julian calendar would all be numbered based on the presumed year that Jesus was born, i.e. “year one” (there has never been a year zero under either the Julian or Gregorian calendars). From this he calculated that the present year was 525, and eventually this numbering became standard throughout the Western world.
Naturally, by 525 AD the Christian religion was already a powerful force in Europe, and since it was a monk who invented the new numbering scheme, of course he would have seen the birth of Jesus as the most important event in history. Regardless of whether this is a correct view or not, the system gained popularity and is now used throughout most of the world. In other words, the years have historically been calculated by the belief in Jesus as it was understood five centuries after he died. And belief in Jesus is something that definitely exists.
So now you know. And knowing is half the battle! Thanks for writing.




  1. Robert, not Bob says

    Reminds me of the time someone told Matt he couldn’t be an atheist because he had a biblical name. ‘Course that guy was probably joking.

  2. says

    On a similar note, I’ve seen some amazing overreactions to the use of CE and BCE. Some religious types flip out if you don’t use the religious abbreviations (AD, BC).

  3. Scott says

    I am the one that asked the question, and for clarity I am an Atheist and I wanted to pose the question as a Theist would.

    Thank you!

  4. Pierce R. Butler says

    … the older Julian calendar, so named because it was created by Julius Caesar in 46 BC.

    Not invented, but officially instituted by Julius Caesar.

    From Adrian Goldworthy, Caesar: The Life of a Colossus:

    One of Caesar’s most lasting projects was the reorganisation of the calendar, and again this showed Hellenistic influence with the Alexandrian astronomer Sosigenes playing a leading role in the calculations. Rome’s existing calendar consisted of 355 days, was based originally on the lunar cycle and needed constant modification. The college of pontiffs – of which Caesar was the most senior – were charged with adding extra or intercalary months at their discretion in an effort to keep the official year at least vaguely connected to the seasons of the natural year. It was a confusing system and one open to political manipulation, for instance, extending the year of office of an associate. During his time as proconsul of Cilicia, Cicero had been very nervous that someone would do this and thus postpone the date on which he could leave and return to Rome. By the time of the Civil War the calendar was running some three months ahead of the actual seasons.

  5. Frenzie says

    Because it doesn’t stand for Christian Era, but for Common Era. 😉

    I don’t particularly care either way — although Before Christ and After Christ would make more sense than BC and AD — but Richard Carrier is quite unhappy with (B)CE. Here’s a reply that focuses on the alleged inclusiveness of (B)CE. I’m more inclined to side with Carrier.

  6. Frenzie says

    PS I saw the /trollface, but I reckon explaining it wouldn’t hurt potential onlookers.

  7. says

    besides the european calenders, there are loads of varients,

    like the hindi calender

    or the Islamic one: 1435 AH
    Tibethan one: rabqung 17 lo 28
    Yoroba Calender: 10056th year
    Dangun calender: 4347
    Bengali calender: 1421

    ANd last but not least the more famous ones are the Mayan and Chinese Calender

  8. L.Long says

    ” the system gained popularity and is now used throughout most of the world. ”
    Actually it was more like it was forced down the European throat by a powerful church then forced onto everyone else by the economic power of the west. But it did make for a common standard.

  9. CompulsoryAccount7746, Sky Captain says

    a Christian monk in Romania named Dionysius Exiguus invented the concept of the Anno Domini era.

    Ah, we got our dating system from Dionysius, not Jesus. : P
    From Wikipedia…

    “The Graeco-Roman name Dionysius, deriving from the name of the Greek god Dionysus, was exceedingly common, and many ancient people, famous and otherwise, bore it. It remains a common name today in the form Dennis (Denys, Denis, Denise).”

    Praise be to Dennis. \o/

  10. CompulsoryAccount7746, Sky Captain says

    You’re just so depraved, he had to die a second time to make up for it.
    Or this…
    Video: Robot Chicken – Jesus and the Argonauts

  11. OverlappingMagisteria says

    And ironically, Year 1 is one of the years that Jesus was not born on, if the gospel accouts are to be believed. Matthew puts his birth before the death of Herod (4 BC) and Luke puts it during the reign of Quirinius (6 AD onward). So if either of those got it right, Year 1 is still wrong.

  12. OverlappingMagisteria says

    Please don’t do that.

    I know you mean well, but I’d rather see real questions from real theists. If there are actual theists who believe that this is a gotchya question, then let them ask it. There is no need to invent a false character just so that we can laugh at their silly question.

    I know the hosts of Atheist Experience don’t like it when atheists call to the show in pretending to be theists. I assume that applies to email and the blog as well.

  13. beammeupscotty says

    I am glad someone pointed this out. Many cultures do indeed still use entirely different calendars. Some, like the Thais, take full advantage of that fact by celebrating the Western, Chinese and their own Thai New Years. The Thai new year, Song Kran is the wildest of all their celebrations and has developed into the biggest water fight in the world. Trust me, there is nothing quite like traveling down a highway at 50 KPH on your motorcycle and getting hit with a full bucket of water traveling at 50 KPH in the opposite direction. The Thai New Year is not for the faint of heart.

  14. beammeupscotty says

    Considering all the other stuff they got wrong, I can’t see worrying too much about the fact that they got the birthday wrong.

  15. lpetrich says

    Adding extra months for friends to stay in office longer– that’s temporal gerrymandering. Any documentation of it from primary sources? I don’t want to repeat an urban legend.

    The original system of counting years was the year-reign or regnal-year system, which would make this year Barack Obama 6, Elizabeth II 63, etc. As you can see, it turns into a big mess very quickly.

    So over the centuries, various people have invented various zero points for longer-range timekeeping, and the BCE/CE one is the one that eventually won. I would have preferred something like AUC, after a calculated date of the founding of Rome.

  16. CompulsoryAccount7746, Sky Captain says

    From Wikipedia – Roman Calendar

    “If managed correctly this system could have allowed the Roman year to stay roughly aligned to a tropical year. However, since the Pontifices were often politicians, and because a Roman magistrate’s term of office corresponded with a calendar year, this power was prone to abuse: a Pontifex could lengthen a year in which he or one of his political allies was in office, or refuse to lengthen one in which his opponents were in power.”

    The citation links to a latin document called “De Die Natali” by Censorinus in 238 CE.
    English translation

    “The care of correcting this inexactitude was given to the pontiffs, and full power was vested in them for making the intercalation. But, most of them being influenced by motives of resentment, or else of friendship, a magistrate was often deprived of his functions, or held them a longer time, as the pontiffs willed.”

  17. Scott says

    yes, it was a serious question. The reason I posed it in the was that I did is so I would get an aswer as if a theist would ask. I am an atheist.

  18. Matt Gerrans says

    Well, instead of trolling, you could have done the research yourself. That’s what a real Atheist — with a capital A — would do.

  19. CompulsoryAccount7746, Sky Captain says

    IIRC, I heard in a TTC Dead Sea Scrolls lecture series that Pharisees sometimes fudged the length of months to avoid the inconvenience of having a holiday (fasting) right after a sabbath (no work, like cooking). Holidays were fixed, so they shifted the calendar around them.
    The other Jewish sects at the time (Essenes and/or Sadducees) frowned on this, among other less-than-strict interpretations of their laws.
    * I can’t find a citation for this trivia.

  20. Scott says

    Russell said the following: “I thought it would be easy to find a concise answer to this, but it turns out I had a bit of a hard time. So I’m showing my work! You’re welcome.”

    Part of being an atheist is asking questions, and no I was not trolling at all. I want to be prepared when these questions come up. That’s it.

  21. Matt Gerrans says

    Well, can a fictional character technically have “birthday?”

    “…the years have historically been calculated by the belief in Jesus as it was understood five centuries after he died.”

    This assumes he ever lived, which is unproven and which, based on conflicting Biblical accounts (see comments above), is a pretty tenuous conclusion.

  22. adamah says

    This part struck me as interesting:

    “By the time of the Civil War the calendar was running some three months ahead of the actual seasons.”

    Modern people often anachronistically project their modern World view and conceptions of dates/time into the ancient past, where it simply didn’t exist. Ancients were generally more aware of astronomical events (eg solstice, etc), but whether this percolated down to the average plebe is highly doubtful.

    Point being, even if ancient documents reflect a certain date, given the generalized uncertainty and errors that are known to have existed at the time, all such dates must be taken with a HUGE grain of salt since the ancient writer may have been off by a few months (!) and unaware of it.


  23. OverlappingMagisteria says

    “Well, can a fictional character technically have “birthday?””

    Sure they can. Harry Potter was born on July 31, 1980. But if someone said he was born in 1780, that would be wrong given the descriptions of cars, trains, TVs, etc in the rest of the book because it is grossly inconsistent with the story. And Jesus’ birth date of 1 AD is inconsistent with his stories.

    I happen to think that there was a historical Jesus but the accounts are so conflicted because they were written decades afterward by people who had no problem changing and inventing a few things to suit their purposes.

  24. Sadako says

    Yup, it’s Heisei 26 in Japan right now, and 100 years ago, it was Taisho 3. Coins all show the era of the Emperor they were struck in. Many official forms in Japan will call for your birthdate to be given according to era, not Gregorian year, so there will be an option to circle for ‘Meiji/Taisho/Showa/Heisei’ and then you write in the year of their reign. When Japan uses the Gregorian calendar, it’s purely to humor Westerners.

    North Korea uses the Juche Year system, which is based on the birth of Kim Il-Sung (1912 is Juche 1), so in the DPRK, it’s currently Juche 103.

  25. Matt Gerrans says

    It seems to me strange to believe something (eg. a historical Jesus) for which there is no real supporting evidence.*

    * Obviously not including stories/legends/myths, otherwise we should also believe in a historical Odysseus, Thor, Harry Potter, etc. Read the NT closely and there are many details that make it clear that it is not reportage (or even “narrative” as Xtians like to call it), it is fiction and each of the many anonymous authors of it has a different agenda to pursue with his make-believe stories.

  26. nibor says

    I think this year counting after Jesus is outdated. The invention of the computer was an at least as important event as birth of some religion modifier. Therefore, we should start with the year 1941 as year 1 as Konrad Zuse’s computer Z3 was the first working computer. This makes us living in the year 73 aZ3.

  27. Aureolus says

    In ancient times, generally speaking, local dating systems were used within indivdual local areas. As time passed these dates were used in ever expanding areas, coalescing and combing by mutual agreements, merging of regions, take-overs, wars, etc. Quite often these dates were the regnal dates of various rulers, whether local or abroad.

    For example, dates in the area that is now the middle-east (ie: Syria and surrounds) were generally under the Seleukid dating system from about the 3rd century BC onwards, dating from the beginning of the reign of Seleukos I (one of the generals of Alexander the great). Other areas used dates begun by or in honour of Julius Caesar, Pompey the Great, and other individual rulers, such as many of the Ptolemies (including Cleopatra VII – the famous one). The list goes on.

    At Rome, the dating system was taken from 753 BC, which was 1 a.u.c. (ad urbe condita). Thus Julius Caesar was adjusting the dates and realigning the calendar in what is our 45BC, but what was then 709 a.u.c. If you were somewhere else in the world at that time, your own calendar date would be another number altogether, calculated from the beginning of another ruler’s reign, or in some cases from a particular event.

    The Gregorian calendar began to be introduced in the late 16th century, but even that took several centuries to more fully take hold (with its ten+ day intercalary adjustment). It was only in the 20th century that ‘most’ calendars were aligned, some as late as the 1920’s, though some older calendars still remain in local use.

    A fascinating subject, even though the original question was . . well, . . questionable.

  28. lpetrich says

    Thanx for digging it up. It’s nice to discover that it isn’t an urban legend.

  29. Ron says

    Thanks for your honesty and your inquisitive nature. That was a fair question and I learned a little by reading Russell’s reply.

    To everyone else:
    Good grief, stop persecuting Scott! He did not “troll”, he did not mis-represent, and he was curious so he asked a question! The reply was provided for everyone, as a resource for anyone else who was interested’s benefit. Why are we chastising one of our own for the misdeed of seeking to expand their knowledge? I know that the A.E. blog isn’t necessarily an “Answer Desk” but in my book we should be encouraging research and asking questions. We should be a warm, welcoming community.

  30. Scott says

    Thank you Ron for the kind words, I will be honest, I was a little taken back by some of the replies in this thread. I was not expecting the accusations or grammer lessons. But as stated, I want to know how to answer when certian questions come up.

    Thank you again for making me feel welcome.

  31. Baby Bertrand says

    The Mayans had a calendar that needed correction/adjustment less often than the gregorian. Or so I have been led to believe.