2700: The Non-Roman Origins of Roman Numerals | May 12, 2024

Unlike other letter-based numerals that use the letters in ascending order of the alphabet, like Greek or Hebrew, Roman numerals are more abstracted, and somewhat systematic. For instance, X is 10, and take ½ of that for V (5), which is the top half of X. The X is probably derived from adding on an extra line at the end of a set in an early tally marks system. This works the same in M (1,000) and D (500), but not in the way that you might think. 

These letters are not tied to words, though M was reinforced by Latin ‘mille’ for ‘thousand’, and the original form of M in numerals was ↀ, half of which is D. This originated in pre-Roman Etruscan numerals, that used C (100), IↃ (500), and CIↃ (1,000) and these bracketed-I forms then were written as similar looking letters, and C reinforced by ‘centum’. In fact, though not as typically used, other forms ↁ (10,000) and ↂ (50,000) exist from this system of adding brackets. The shapes of the letters, and some Latin words may have slightly influenced the form of Roman numerals as in the case of ↀ→M, but in almost all other cases (I,V,X,L,D) these symbols only coincidentally looked like letters and have nothing to do with the words they represented.