Why Do Some Clocks Use the Roman Numeral IIII and not IV?

Roman numerals are one of the most classical designs on clocks and watches. However, there is a curious detail on the dials of these clocks, which makes many wonder. Anyone who has basic knowledge about Roman numerals must have noticed that most of the clocks and watches use IIII instead of IV on their dials. What are the reasons for this odd phenomenon? Why would clockmakers inscribe the number 4 ‘wrongly’? Well, there is no definitive answer to this question and we may never precisely learn the reasons. However, there are a few theories that give us some insight…

Theory 1: IIII Is Already IV

While the correct notation for 4 is IV, Romans originally wrote their numbers based on the additive principle and signified 4 as IIII. The subtractive notation -IV- actually became the standard after the fall of the Roman Empire. Therefore, the Romans initially engraved IIII on many of their sundials and to signify the number 4. Thus, it is argued that this existing tradition was adopted and continued on mechanical clocks in Europe, when they were first created in the 13 century. However, it is not exactly known why clock makers chose IIII at a time when IV was already widely known and accepted.

Theory 2: Not to Upset Jupiter

Another theory explains the ‘IIII’ phenomenon in relation to the supreme deity of the Romans, namely Jupiter. Being the god of the sky and lightning, Jupiter’s name was spelt as IVPPITER in Latin. It is argued that the Romans did want to offend and upset Jupiter by engraving the first two letters of their supreme deity’s name on sundials or other artefacts. According to this theory, they used IV instead of IIII and this tradition was continued by clock makers when sundials were replaced by clocks.

Theory 3: Symmetry and Aesthetics

Another possible explanation is based on aesthetics, symmetry and visual balance concerning the dial. If you observe how Roman numerals are placed on a clock’s dial, you will notice that IIII and VIII balance each other on the below part of the dial as if they are somewhat symmetrical. Using IV instead of IIII would not create the same radial effect. Therefore, it is commonly accepted that IIII brings a visually balanced, harmonious and elegant look to a dial. By using IIII, a clockmaker creates three separate areas on the dial; one third of the dial consists only of I’s, the second features I’s and V’s with the last third using I’s and X’s.

Theory 4: Easier for the People

A fourth hypothesis suggests that reading IIII on sundials and later on clocks was easier for the common people. One should remember that both in the Roman era and the Middle Ages, most of the European population was illiterate and innumerate. Reading ‘IV’ would require the knowledge of both subtraction and subtractive notation of Roman numerals. Also, it could easily be confused with VI. Therefore, it might be argued that IIII was used instead of IV for the sake of simplicity and practicality so that everyone could be able to understand and tell the time. This theory also points out that because of the same reasons, some clocks represent the number 9 as VIIII instead of IX, which is the correct version. According to this theory, clockmakers continued using IIII as a cultural tradition in the modern times.

Theory 5: Easier for the Clockmaker

A fifth theory suggests that using IIII instead of IV was easier and less expensive for the clockmakers. According to this theory, by applying IIII on dials, clockmakers could create all the numerals by using fewer moulds.

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