For example, I usually use

  • 560 BCE
  • 1066 CE

As opposed to the traditional:

  • 560 BC
  • AD 1066

Some people, when using AD, place it after the year:

  • 1066 AD

How are epochs commonly denoted?

  • This could have been a good question, but instead it was written as an opinion poll. Commented Feb 12, 2015 at 4:19
  • ...so rewrite it so it's not an opinion poll; don't just mindlessly vote to close.
    – phenry
    Commented Feb 13, 2015 at 21:14

9 Answers 9


Commonly, BC follows the date and AD precedes the date when referencing a specific year. Wikipedia suggests this is because English copies Latin usage of placing the abbreviation before the year number. Since AD is a latin phrase and BC is not, we arrive at 535 BC and AD 1066. Not the most compelling objective argument, I admit, but entirely plausible considering the other odd constructions we've kept around simply because of Latin tradition.

When referring to a century as a whole in text, the convention of placing either BC or AD after the stated century is considered acceptable by most of the style guides I dug up.

Wikipedia goes further to note that CE and BCE are becoming increasingly common in academic and religious writing, and suggests that CE and AD should not be used unless the date or century would be ambiguous without it.

As an aside, I remember seeing one unusual date-reference acronym that was a good five letters long. It had to do with radiocarbon years, if I recall correctly. The full acronym escapes my memory at the moment, but hopefully someone will read this and chime in.

  • 4
    Wikipedia isn't quite right in this. It isn't that AD is Latinate that determines its position, rather, it's the meaning of AD and BC, respectively, that guide their usage. If we write these out whole, watch where the dates go: "In the year of our Lord, 1066." "550 years before Christ."
    – The Raven
    Commented Apr 7, 2011 at 14:42
  • An interesting postulate. I admit I have never seen the Latin equivalent of BC, A.C.N. or lit. before Christ (was born) used before a year. It'd be interesting if we dug up an example of such.
    – HaL
    Commented Apr 7, 2011 at 15:03
  • 1
    Radiocarbon dating uses BP (before present) where present=1950, so you can have -ve BP ages! There is also calBP (calibrated BP) which adjusts older dates to account for our now knowing the original concentration of C14. There is a move to change all the dates, since the original inventors had the wrong half-life, but no-one can face the confusion!
    – mgb
    Commented Apr 7, 2011 at 15:21
  • @mgb A-ha, that's it! Now I remember: RCYBP, or radiocarbon years before present.
    – HaL
    Commented Apr 7, 2011 at 15:29

I write BC and AD after the numbers. The BCE and CE just strike me as silliness.

  • 3
    ...My question has always been what do the proponents of the Common Era think makes it common? If we're going to keep using the primacy of Christianity to delineate "then" and "now," why bother changing the classical terminology? What does it signify? I really have never understood the idea behind the practice...If this seems too rant-ish, feel free to delete.
    – kitukwfyer
    Commented Apr 7, 2011 at 14:50
  • @kitukwfyer - exactly. If I quote an egyptian date as in "the Nth year of the reign of X" I'm not forcing the belief in a particular god-pharoah on anyone. But by saying that AD=CE=common era I'm effectively saying that this is the correct,common,real date and any other dating such as AH is odd.
    – mgb
    Commented Apr 7, 2011 at 15:25
  • 1
    I'm inclined to agree; but while BC is fairly objective, I can understand people who don't like to use AD. It's not widely understood now, but originally referring to "AD 2011" is not relating 2011 to some event, but describing it as "the year of the lord 2011", so accepting the messianic nature of Jesus. I think arguing in this way today is a species of etymological fallacy, but I can see why some people might seriously adopt the argument.
    – Colin Fine
    Commented Apr 7, 2011 at 16:01
  • I suppose if it was Before-Jesus that might be OK but Christ has a religious meaning. I always wondered why BC isn't in Latin, was there no need to talk about dates BC before the 19C?
    – mgb
    Commented Apr 7, 2011 at 16:46

You should adopt the practices of wherever your writing will end up. If you submit to a paper or journal, check their style guides or ask an editor which they prefer. Schools and their professors will often have a preference and following their lead shows them a few things:

  • you care about style
  • you notice small details
  • you are willing to defer your personal preferences
  • keeps the overall style of the paper, journal, whatever coherent and consistent
  • the copy editors will love you for it
  • 2
    +1 It's always best to write for your audience, no matter how silly/misguided their preference may seem to you.
    – kitukwfyer
    Commented Apr 7, 2011 at 14:53

I suggest we all start using Unix Time which is the number of seconds elapsed since midnight Coordinated Universal Time (UTC) of January 1, 1970, not counting leap seconds. So for instance, as I'm writing this it's 1302186003. Battle of Hastings: -28502703439. Here's a red-letter date in the history of science: November 5, 1955 or -446722639.

  • Or, even more obscure, Swatch Internet Time. See you @646.beat!
    – EmmyS
    Commented Apr 7, 2011 at 14:33
  • Or use stardate :D
    – jsj
    Commented Apr 7, 2011 at 14:33
  • Also, lol @ 5/11/1955 (You must be as old as me to remember this special day in the history of temporal physics)
    – jsj
    Commented Apr 7, 2011 at 14:35
  • @Sam and @Tri are we talking flux capacitors here?
    – mplungjan
    Commented Apr 7, 2011 at 14:52
  • The question was "how other people denote epochs" The Unix epoch is January 1, 1970. I can't say what answer will be helpful to the OP, so whether it's helpful or not is up to them, but it's certainly on-topic.
    – Sam
    Commented Apr 7, 2011 at 15:33

There is Anno Mundi, or AM/A.M. which is used in the Jewish calendar. It denotes the Year of the World, so traditionally speaking, there aren't any dates before this. It is 5770 AM currently. Traffic and News on the hour. (sorry)


Going to their meaning:

560 Before Christ


Anno Domini 1066 = In the year of the Lord 1066

Grammatically the only way to place them that makes sense is BC after the year and AD before the year. However, as abbreviations that is not as obvious, so either is still usable in the ‘wrong’ place without causing havoc. “BC 560” can not reasonably be misinterpreted as “Before Christ number 560”.


Seems like this is mainly an issue when you're referring to dates BC/BCE, since if you cite the date "1970", for instance, most people are going to know you mean in the present era, not the ancient one. (That gives me a thought: why not use mathematical signs, + and -, as the designations, so that 2000 BC/BCE would be -2000? Maybe a letter would have to be inserted, such as "Y" or "A", so it would read -A2000, so it could be distinguished from regular mathematical functions.) Anyway, the use of the word "common" in the CE designation doesn't really bother or offend me politically or religiously because of the assumption that it's more "real" or "correct". I put it in perspective with a little humor remembering the other meaning of "common": Vulgar, course, boorish, uncivilized, unrefined, low-class, inferior, etc.


I personally would write BC and AD after the year.

I personally feel that BC/AD and BCE/CE and writing the designations in front of the year are all correct, and all function the same, but BC/AD is more universally accepted, don't you think?

  • Yeah pretty much, just wondering if there are any strong views on the matter.
    – jsj
    Commented Apr 7, 2011 at 14:13
  • @trideceth: So you are trying to start a flame war?
    – MrHen
    Commented Apr 7, 2011 at 14:14
  • @MrHen :p not really, just interested in people's usage
    – jsj
    Commented Apr 7, 2011 at 14:18

YBP = years before present is straight forward and used in the sciences.

  • 2
    Could you back this up with clear references. I have never come across this acronym before. Wouldn't present be confusing and ambiguous? The "present" will be different ten years from now.
    – Mari-Lou A
    Commented Feb 12, 2015 at 8:50

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