Roman Numeral Clock Discovery

Well, I was laying in bed one morning a couple of days ago after I had just woken up.  I was just casually glancing around the bedroom, thinking random thoughts while trying to get motivated to hop out of bed.  I have a big clock on the wall in my bedroom that belonged to my grandma.  Here's a picture of it:

I have always enjoyed looking at this clock.  My eyes will just go from number to number, clockwise, and it's just somehow fun and soothing to me.

So there I was, moving my eyes around the dial, thinking "5", "10", "15"...in my head, when all of a sudden it dawned on me.

I got to the "4", and noticed that the Roman numeral said "IIII".  And I was like WAITAMINIT.  Isn't the Roman numeral for "4" "IV"?!?

So there I continued to lay in the bed, my eyes burning holes on the "IIII" of that clock like lasers.  I was confused.

Eventually Lilly (who was asleep next to me) woke up, and the first thing I asked her was, "Lilly, what's the Roman numeral for "4"?  And she sleepily replied "IV".  And I told her about the clock on the wall saying "IIII" in place of the "4" instead of "IV".  Lilly was completely nonplussed, and explained that on a clock, you can use either "IIII" or "IV" for the "4", and either one is correct.

And I was like:

I found that hard to believe.  I just knew it probably had to be some kind of mistake.  And even more mind-blowingly, I'd stared intently at that very same clock for the past 30 years, and never noticed that the "4" said "IIII" instead of "IV"!!!

So yesterday, I checked all the other clocks I have with Roman numerals on their faces, and lo and behold, they ALL had the "IIII' where the "4" should be!  I was flabbergasted!  Here's the evidence:

(This one was at my brother & sister-in-law's house):

So I Googled it, and as it turns out, Lilly was right (are you smarter than a 5th grader?  LOL).  It's perfectly acceptable to use either "IIII' or "IV" for the "4" on a Roman numeral-faced clock.  There are a couple of theories about it, but nobody knows exactly why.

Then I took a notion to Google again and check to see what's on the face of the most famous clock in the world (Big Ben in London -- which "Big Ben" is actually the name of the bell inside the clock; not the entire clock itself)...but anyway...see for yourself what ol' "Big Ben" has for the "4":

What's that?  Well, well, well...if it ain't a big ol' "IV" in the place of the "4".

You never know what you're gonna get!  I'm glad I discovered the "4" / "IIII" / "IV" thing, but I have a feeling it might drive me a little crazy!  (Hmm...I wonder what's on the clock at our historic courthouse in town)...I'll have to go check and report back...!  :P