I enjoyed SD Classic #1 (02/23/1990) on Roman numerals. No wonder Rome fell.
This – the column, not the fall of Rome – got me searching for online Roman numeral conversion facilities. Google has one (e.g., “999 in roman numerals”), but it doesn’t handle numbers higher than 4999. Then I found this:
This courteous robot explains how it got its result, and has an upper limit of 999,999. It also appears to have the virtue of consistency in its method of calculation. (Proof of this theorem is left to others.)
Funny that they apply the rule that (something) = 1000*something for all, except M, for which the SD article contained the notation (I), consistent. Then I suppose this is like a number system - just put a () to multiply by 1000.
The Rome Republic started in 509 BCE and the Empire was divided into two in 364. That’s over 850 years of Roman numerals. In fact, Roman numerals were used exclusively in Europe until Fibonacci introduced Arabic numerals to the Europeans in 1202. It would not surprise me if Roman Numeral evolved in their use and various ways of writing them came and went over time.
I have a hunch that what we think is the correct way to write Roman numerals was probably created in the Victorian era.