Meet “Mercedonius” the annoying month that used to exist (sometimes)

There are many reasons to be thankful for the benefits of modern living ― antibiotics, airplanes, velcro . . . Another subtle but essential item is our calendar. It may have some frustrating moments, but consider how months used to work. Take heed of Mercedonius.

In the days of the Roman calendar, an intercalary month was added in leap years and a few other times as well. This month was called Mercedonius, but it was also known as Intercalaris.

(The insertion of a leap day, week, or month into some years is called “intercalation.” Intercalation is done to align the calendar with the seasons or moon phases.)

The name Mercedonius comes from the Latin word “merces,” which means “wages.” It got its name because workers were paid at the time of year Mercedonius occurred, around the month of Februarius.

The addition of Mercedonius didn’t happen automatically. The decision was made by the high priest of the College of Pontiffs, who was also known as the Pontifex Maximus. The Pontifex Maximus, Latin for “greatest bridge-maker,” was the head honcho of the ancient Roman religion.

(As we end January, learn the name of the unusual Roman god who is the month’s namesake, and the meaning behind his two faces, here.)

The Pontifex Maximus was supposed to base the decision whether to include Mercedonius in any given year so that the calendar would correspond with the seasons. Politics, however, are said to have motivated his decision making. For example, Mercedonius was sometimes inserted to allow a government official to stay in office longer.

You can imagine the confusion that this caused. If you were living outside of Rome, you might have no idea what the current date was.

In 46 BC, Julius Caesar introduced the Julian calendar and did away with Mercedonius. Can you guess the month that was named in honor of him? Find the answer, here.


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  2. Paul -  March 23, 2013 - 1:53 pm

    This article hardly touches on the confusion that existed in the Roman calendar before the introduction of the Julian calendar. Many calendars in the ancient world were confusing. The Egyptians used to observe three separate calendars simultaneously.

    As I recall, the Roman Empire was observing an eight-day week during the first century. I’ve heard that, as the Jews spread through the Empire and became notably businessmen and bankers, their observation of a seven-day week encouraged the same by those who worked with them.

    I believe the Chinese, Japanese, and others around them observed a lunar (or lunar-solar) calendar with three weeks in each month, each about ten days long. There was a specific character (not the one currently used for “week”) that was used and prefixed by either “beginning”, “middle”, or “ending”.

  3. Gruntly -  January 31, 2011 - 11:42 pm

    And also, thank you as well for the knowledge Frankie…

  4. Gruntly -  January 31, 2011 - 11:39 pm

    @Isabella and Curly.

    I agree with Isabella. Actually the Mayans didn’t use the 7 day week, nor would any civilization not related to Christianity. The earths physical placement has no correlation with weeks, whereas, days, months, and years do. And the influence of where the 7 days came from is beyond my knowledge at the moment. I can only assume it was pushed heavily by something to do with politics…

    • Esoteric Poet -  April 4, 2016 - 3:12 am

      Christianity; from the Genesis story of the creation of the world.

  5. Isabella -  January 31, 2011 - 12:23 am

    Thanks for the info about Mozambique, Frankie. The bit about the finger segments is very clever, but I think maybe too clever for primitive use. The weeks representing quarters of the moon sounds great, but gets me wondering if actual weeks neatly coincide with the quarters. I never could learn the gear shifts in a car – it stopped me learning how to drive. Co-ordination is my dumb area.

  6. frankie -  January 30, 2011 - 4:31 pm

    @ Isabella – you’re absolutely right. I used to live in an area of Mozambique where (until colonisation) people observed a five-day week. I was told that was because they could be counted on one hand and – with hot weather and easily perishable items for sale – the fifth day being the market day made more sense.

    On the other hand, especially if one uses fingers for counting and the moon for keeping track of time, there are 28 segments of the fingers on both hands (palms up, counting the spaces between the joints – possibly making counting out a fortnight – fourteen nights – easy?), the lunar month is about 28 days, and there are four phases of the moon that are easily identifiable:
    new moon to first quarter (via waxing crescent),
    first quarter to full moon (via waxing gibbous),
    full moon to last quarter (via waning gibbous),
    last quarter to new moon (via waning crescent).
    But that’s just my conjecture.

  7. ag -  January 29, 2011 - 6:11 pm

    @ smoothius… does kate have balls? lol=))

  8. smoothius -  January 29, 2011 - 8:08 am

    sorry kate but i think i can speak for many of the regulars here on hotword that cyberquill’s remarks are generally witty, entertaining, and well received. maybe you should ‘take your ball and go home’.

  9. Moon Doggie -  January 29, 2011 - 5:06 am

    It is fascinating to watch how passionate we can get about words and our communication systems… words are simply symbols that represent concepts that can mean very different things to different people.

    And, as a quick aside… as I read through this blog, I get the strong impression that some people should not share the ‘inner mental dialogue’ that they are having with themselves…

    it tends to scare the other natives, and confirms the fragility of our systems for communicating logical concepts.

  10. Anonymous -  January 28, 2011 - 2:30 pm

    I’ve heard that Julius Augustus invented the months July and August, or SOMETHING like that.

  11. Isabella -  January 28, 2011 - 1:22 pm

    Whoops – verbo is Italian. The Latin, if my rapidly deteriorating memory serves me, is “Verbum” – second declension neuter. I have a memory like Jimminy Cricket – sitting on my shoulder and prodding me from time to time in a very critical manner. Still, it’s just fun, isn’t it? The capital letter for Verbum I really do think should be there – it is not just any old verbum, is it?

  12. Isabella -  January 28, 2011 - 10:41 am

    But what about the Chinese, Curly? I mean, they didn’t have the Old Testament, did they? Years are natural. Months are natural. Days are natural. Without the Bible, I am not sure that weeks should even exist.

    And here’s me with a good A level in French forgetting about the capitals! I knew there was something niggling! Thank you Vince S!
    In principio erat Verbo. I bet I’ve forgotten some of the Latin as well!

  13. melissa -  January 28, 2011 - 10:05 am

    don’t know what ur talking bout but i’ll just go with the flow. :-]

  14. pizza -  January 28, 2011 - 9:17 am

    dinosuars rule

  15. muelswyf -  January 28, 2011 - 9:14 am

    Tootsday (refers to drugs, NOT flatulence)
    Weekend Eve

  16. DIVVIE -  January 28, 2011 - 7:01 am

    WOW, it’s getting crazier and crazier every day. The IT I refer to is this blog

  17. Xero -  January 28, 2011 - 6:20 am

    Does this blog even do any research, or do we just get all of our “facts” from wikipedia or something? Does a high school student write this drivel?
    You should all run from this blog and try opening an actual book instead of believing all of the crap that’s on the internet. There are actual scholars out there doing actual research that you could really learn from. Try not to take some pseudo intellectual site whose only real purpose is to sell ad space too seriously.

  18. Aporia -  January 28, 2011 - 5:36 am

    @Abby: True, but in English we also spell “u” as “you.” Just a heads-up. :)

  19. Vince S -  January 28, 2011 - 5:12 am

    When u are talking about months in French and Spanish you DO NOT CAPITALIZE!!!!!
    I’m sorry, but that frustrates me so much!
    It is “mercredi” rather than “Mercredi” and “miércoles” rather than “Miércoles”…

    Whoa Abby, calm your s*** down. That is no reason to go postal, and or al-Qaeda, its not like people here are trying to educate future generations. nOw tEll mE; d0Es tH1S sTAtemenT mAk3 U aLL tWiTChY &Nd HoMiCID@l ?Q??

    • Esoteric Poet -  March 1, 2016 - 1:33 am

      hi Vince S. This is from five years away from you.
      That last sentence of yours makes me want to lay you across my lap and spank you hard before sending you back to second grade English class.
      There should be nothing kinky/lewd in that line above.

  20. yo momma -  January 28, 2011 - 4:56 am


  21. darpu -  January 28, 2011 - 4:21 am

    The month of July was named after Julius Caesar. :)

  22. jacko23 -  January 27, 2011 - 11:32 pm

    The days of the week came from the Norse. Monday = Moonday; Wednesday = Woden’s Day; Thursday = Thor’s Day; Saturday = Saturn’s Day; Sunday = Sun’s Day, etc. Google: “days of week; origins”

  23. hi -  January 27, 2011 - 6:48 pm

  24. Abby -  January 27, 2011 - 6:38 pm

    When u are talking about months in French and Spanish you DO NOT CAPITALIZE!!!!!
    I’m sorry, but that frustrates me so much!
    It is “mercredi” rather than “Mercredi” and “miércoles” rather than “Miércoles”…

  25. zanger -  January 27, 2011 - 6:33 pm

    i dont even know wat u people r talking about, so i’ll just go with it!

  26. Freshman in High School. -  January 27, 2011 - 5:08 pm

    Dear Girl in HS,
    I was genuinely intrigued by this article, thus the reason I read it.

  27. Curly -  January 27, 2011 - 4:49 pm


    There have been seven days in the week since the beginning of time, as I’m sure you’ll recall if you are even slightly familiar with the Bible. Since then, people have just grown so used to a seven-day week that Napoleon was unsuccessful in his endeavor to change it.

  28. sonia -  January 27, 2011 - 4:28 pm

    I love you, hot word, and your readers with their interesting reactions.

  29. girl in hs -  January 27, 2011 - 3:25 pm

    wow i read this cuz my teacher read it and wanted us to said to read the comments so thats my reason to read this wats urs?

  30. Ale Canaya -  January 27, 2011 - 12:16 pm

    The days in Spanish relate to the planets: “Lunes” (Monday) from “Luna” (Moon – they thought it was a planet), “Martes” (Tuesday) from “Marte” (Mars), “Miércoles” (Wednesday) from “Mercurio” (Mercury), “Jueves” (Thursday) from Jupiter, “Viernes” (Friday) from Venus and “Sábado” (Saturday) from “Saturno” (Saturn). “Domingo” (Sunday) was the day of the sun originally, but later religiosly took the name of “Day of the Lord” (Dies Domini in Latin).

  31. xexexe -  January 27, 2011 - 11:41 am

    I believe Wednesday was supposed to have derived from “Mercury”:

    Sunday = Sun
    Monday = Moon
    Tuesday = Mars (Tiw)
    Wednesday = Mercury (Wodan)
    Thursday = Jupiter (Thor)
    Friday = Venus (Frige)
    Saturday = Saturn

  32. Isabella -  January 27, 2011 - 10:52 am

    And isn’t Mercredi derived from the got Mercury? Jeudi is Jove’s day. Vendredi belongs to Venus, Samedi is named for Saturn. Lundi is the day of the Moon. Mardi is the day of Mars. I can’t remember Dimanche. The “di” bit is another version of “day” – but why “manche”?

  33. Isabella -  January 27, 2011 - 10:46 am

    I see I have successfully submitted the above comment. Any answers will receive my full and eager attention.

  34. Isabella -  January 27, 2011 - 10:43 am

    Coincidentally, there I was sitting drinking my tea and idly wondering why there are seven days in a week. Are there seven days in a week world wide. has any nation (except France under Napoleon?) attempted to have the calendar done differeintly? I think I remember, from years ago, learning that Napoleon had a go at introducing a ten-day week. Is that true or was I misinformed?

  35. JJ Rousseau -  January 27, 2011 - 10:38 am

    We always appreciate Non Sequitur — in the month of Janus we roll — There’s always more than one side to a story — Go ask Alice down in the Rabbit Hole. Oui?

  36. Melissa -  January 27, 2011 - 10:30 am

    These comments are inane, with the exception of Svenjamin.

  37. Markv -  January 27, 2011 - 9:54 am

    I thought about the Mercedonius / Mecredi link, but i think the inversion of the C and R disqualify it.

    Could have a connection to Mercedes(Car) though?

  38. AMY-LOU -  January 27, 2011 - 9:34 am

    Wow.This is really lame i have no reason to even read something this stupid so uh bye!!!!!!!!!!

  39. David -  January 27, 2011 - 8:31 am

    Shouldn’t that be ‘honcho’, rather than ‘honco’?

  40. Kate -  January 27, 2011 - 8:26 am

    good question Svenjamin
    Cyberquill – lighten up – you’re cleverness pales next to your consistant snide comments – this is fun, if you’re not having fun, please take your ball and go home

  41. Waldo Pepper -  January 27, 2011 - 8:24 am

    [...]still first[...]

  42. Ben -  January 27, 2011 - 8:17 am

    i think July has been named after Julius.. and i think they have tackled that on a previous hot word..right?

  43. Svenjamin -  January 27, 2011 - 7:17 am

    Makes you wonder if ‘miercoles’ (Spanish) and ‘Mercredi’ (French), both words for Wednesday are derived from the word ‘merces’. Dictionary.com, any comment?

  44. Tayba -  January 27, 2011 - 7:02 am

    Augustus Caesar named the month of August.

    Julius named July.

  45. Rickedy Rick -  January 27, 2011 - 6:56 am

    Yo. It’s the green machine. Gonna Rock the town without bein’ seen. Have you ever seen a turtle get down? Slammin’ and jammin’ to the new ice sound. Yo. Gonna rock the place, with the sound of the ninja turtle bass. Iceman. Know what I’m sayin’, devastatin’ action, you know I’m not playin’.

  46. juggs -  January 27, 2011 - 6:14 am

    “head honco” or “head honcHo”?

  47. Alex -  January 27, 2011 - 6:02 am

    Cos of the gods, or Angels as they are sometimes known, we have a calendar.

  48. alan -  January 27, 2011 - 5:48 am

    check the spelling for honco / honcho.

  49. Cyberquill -  January 26, 2011 - 7:50 pm

    Can I guess what month was named after a guy named Julius? I dunno. August?

  50. smoothius -  January 26, 2011 - 2:14 pm

    so they only got paid once per year?! they must have been budget masters!

    • Esoteric Poet -  April 4, 2016 - 3:19 am

      because they worked the whole field from preparing the soil, to planting, taking care of the field, harvesting and winter stocking. and they were not even paid in advance.
      nothing to really buy, everything they needed were in those farms. Clothes, yeah, they spend their wages on clothes. :D

  51. MERCEDONIUS | BLOGCHI@mayopia.com -  January 26, 2011 - 1:21 pm

    [...] Mercy Donuts Mercedonius We — Human beans in some Dumpster Stew of intercalary. — If it’s politically feasible, — we simply make it up. — The catsup bottle’s squeezable. — Rousseau still thinks he’s a pup. — There’s more than one way to ‘skin a cat’ — or have a hot dog on a bun. — Mercy, mercy donuts — we’ll call that – ‘Hot Word Chow Fun’. –>>Rupert L.T.Rhyme [...]


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