Yes, ladies and gentlemen, Americans are suddenly interested in Roman numerals. I found the article interesting myself.
And I have only found out about this now. :shock:Decimvs dixit:I remember finding it so interesting that the subtractive principle is optional, and that its systematic use is a relatively modern phenomenon!
Wikipedia dixit:In the early period of Roman history, there was no subtractive principle. Subtractive notation arose from regular Latin usage: the number 18 was duodeviginti or “two from twenty”; the number 19 was undeviginti or "one from twenty"