Longcase clocks (also known as grandfather clocks) typically use Roman numerals for the hours. ("IIII" -rather than "IV"- is often used to mark the fourth hour to achieve symmetry with "VIII.")
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Allegedly because Louis fourteenth liked it that way.
There is also the the supposition that the Romans only added on so 4 would be IIII and nine would be VIIII and not IX. You pays your money and takes your chances.