About a week ago I noticed the clock on my wall didn’t use the usual Roman numeral IV to represent 4. It used IIII.
Did a mistake make it to production?
Nope. It turns out this is extremely common and I never noticed. Nobody seems to know the real reason, but there are several possible explanations why IIII was and/or is preferred over IV. My favorite…
One hypothesis we came up with is that of the “lazy clockmaker”… One that we don’t really take seriously. While this doesn’t apply to clocks with cut-out or painted numerals if the numerals were cast in metal having IIII instead of IV and VIIII instead of IX could have made the clockmaker’s life slightly easier.
If you rely on the additive notation, you’ll end up with these numerals: I, II, III, IIII, V, VI, VII, VIII, VIIII, X, XI, XII. This means that you can create fewer moulds, as you’ll use the same basic mould for the four first numerals and the same basic mould for the numbers from VI to VIIII. Only three moulds would be required: a first one shaped like IIII that was partially filled to create the numbers I, II, III and IIII, a second one shaped like VIIII used to create the numbers V, VI, VII, VIII and VIIII and a last one shaped like XII, used to cast the number X, XI and XII.