<i>> The numerical notation of 4 is IV in Roman numerals.</i><p>Using "IIII" instead of "IV" isn't even necessarily wrong. Rome was a big empire with a widely-distributed populace that lasted for a thousand years. The usage of numerals changed over time and according to context:<p><i>"While subtractive notation for 4, 40 and 400 (IV, XL and CD) has been the usual form since Roman times, additive notation to represent these numbers (IIII, XXXX and CCCC)[9] continued to be used, including in compound numbers like 24 (XXIIII),[10] 74 (LXXIIII),[11] and 490 (CCCCLXXXX).[12] The additive forms for 9, 90, and 900 (VIIII,[9] LXXXX,[13] and DCCCC[14]) have also been used, although less often. The two conventions could be mixed in the same document or inscription, even in the same numeral. For example, on the numbered gates to the Colosseum, IIII is systematically used instead of IV, but subtractive notation is used for XL; consequently, gate 44 is labelled XLIIII."</i><p><a href="https://en.wikipedia.org/wiki/Roman_numerals#Origin" rel="nofollow">https://en.wikipedia.org/wiki/Roman_numerals#Origin</a><p>As for clock faces, the explanation that I always heard was that it simplified the manufacturing process to use IIII rather than IV; something about making better use of materials to have one fewer V and one more I.
The reason that I heard was that it was easy to mass-engrave a single plate:<p>VIIIIX<p>For each clock, you make 4 of these, and split each block into numbers the following way:<p>V IIII I X<p>VI III IX (mirror the IX for 11)<p>VII II IX<p>VIII IIX<p>This lets you mass produce watch numbers with a minimum of wasted material.
IMHO there's an obvious reason not mentioned: due to their position on the dial and convention IV and VI would typically be depicted upside down, increasing the likelihood of confusing them—particularly with a semi-literate populace.
I wonder how much Roman numerals are even taught any longer. Maybe 5 years ago now I was traveling with a friend who went to a solid US suburban high school outside of a major city. Younger than me but certainly not young. And she asked me what a date written in Roman numerals was in the numbering system we normally use. I was somewhat floored.<p>Thinking about it though. It sort of is cultural/historical trivia. How many hours do you spend in school drilling how Roman numerals are constructed rather than teaching something else. I suppose it's nice enough for those who encounter them when traveling. But pretty far on the not-essential end of the axis.
I had heard that IV might be considered sacrilegious, as the god Jupiter would have once been spelled IVPPITER, as I was used for modern J and V for modern U.
Sandi Toksvig made the point in a QI episode that if you use IIII, you get a pleasing symmetry with the number of Vs and Xs on a clock face. Four numbers with only Is, four numbers with a V and four numbers with a X.<p>I'd be surprised if that was the reason, but it's kind of neat.<p>I II III IIII<p>V VI VII VIII<p>IX X XI XII
If Roman numerals are printed around the perimeter of the clock face with the base of each numeral on the same circle, as opposed to printing the numerals horizontally, then the numerals towards the bottom are harder to read because they are nearly upside down. This makes it harder to distinguish quickly between IV and VI. One solution is to use IIII instead of IV.
Fun fact: in Roman numerals there is no <i>standard</i> way to write numbers above 3999. There are basically two competing camps for how to write them. One with C's and backwards C's acting kinda like parens and one with lines over the letters.<p>On the other hand, they had semi-standard numerals for all sorts of odd fractions like 1⁄288 = ℈.
I've always thought the "well balanced and looks better" was the simplest and most likely of the theories out there on why the IIII is used. Dials that use IV just look funny to me, but perhaps that's simply because they're rare.
It's unclear to me when the (now standard) subtractive form became the standard; there are examples in Roman times of e.g. IIX for 8, and VIIII for 9, both of which would be non-standard today.
Heh. When I was a teenager, I once convinced my parents not to buy a clock because it used IIII instead of IV. Clearly a counterfeit!<p>Then we went home and noticed all the clocks in the house had IIII.
I knew that both forms were common because I was lucky enough to have a Latin teacher who assigned as extra credit "write this number in Roman numerals" and also accepted additive notation for this reason. He even argued that IIIIIIIIII could be a valid if cheesy alternative to X based on very early texts, but this might have just been a bluff. I never tried to write 123 as IIIII...III.
This seems like a much better fleshed out exploration of this subject: <a href="https://monochrome-watches.com/why-do-clocks-and-watches-use-roman-numeral-iiii-instead-of-iv/" rel="nofollow">https://monochrome-watches.com/why-do-clocks-and-watches-use...</a>
My dad has fixed old pendulum and wind up clocks for years as a hobby. He also fixes old tube radios. There are half a dozen to a dozen clocks around his house at any time. Some have IIII and some have IV. I can't say I've seen one more than another.
As kibwen said, there wasn't a clear "standardized" form. Most rules were invented much later. "IC" was perfectly understood by Romans that would have used "MXMII" without a second thought.<p>The reason of "IIII" is of usability for clocks that can be seen from different angles. Six can only be written as "VI" so "IV" is changed to "IIII" to prevent confusion.<p>Of course there are all kind of urban legends and fake stories of kings requesting the number be written this or that way.<p>In case someone doesn't know, a fun fact: "I" is one finger, "V" represent the open hand (think pinky and thumb in angle) and "X" both open hands united. So 1, 5, 10.
I still remember vividly how I once wrote IIII instead of IV in an outline numbering at school and my teacher was furious about it and basically told me I was stupid for writing it that way.
So glad these days are over.
According to The Internet, this:<p><a href="https://web.archive.org/web/20201115002205/https://www.washingtonpost.com/blogs/arts-post/post/public-clocks-do-a-number-on-roman-numerals/2011/11/04/gIQAenKllM_blog.html" rel="nofollow">https://web.archive.org/web/20201115002205/https://www.washi...</a>
In Latin, sometimes numbers have synonyms, like 18 (two from twenty or eight and ten). In my mind, the Roman system was very obvious. Then I learned to read a little French, and had genuine curiosity about the reasoning behind this soixante-dix-neuf character.<p>edit: sometimes I wonder if arithmetic arose simply from naming numbers
It took me a minute to realize that I even had a clock in the house with Roman numerals! Yes, it uses IIII.<p>You'd think it would be easier to remember given that I had to change it less than a week ago.
"The Mystery of Numerical Notation on the Dial Plate - 4 is Expressed as IIII, not IV"<p>Here is the uneditorialized headline. Especially it is called dial plate, not clock face.
It's odd that they still use IX though, since that is indistinguishable from inverted XI (IV and VI, by contrast, are distinguishable even after rotation).
When talking about wrong usage of Roman numbers, the first that comes to mind is a well known, and much copied, tattoo that writes 1975 not as MCMLXXV.
But its not<p>Doc Brown can’t be wrong:<p><a href="https://clickamericana.com/wp-content/uploads/Back-to-the-Future-III-Clock-tower-in-1885-1536x954.jpg" rel="nofollow">https://clickamericana.com/wp-content/uploads/Back-to-the-Fu...</a>