[thaumasiotes]

Note that our use of D and M for the "Roman numerals" 500 and 1000 is a misinterpretation of their |) and (|).

[Y_Y]

Can you really argue that this use is a "misinterpretation" and not just the usual evolution of written symbols?

[thaumasiotes]

Yes, D and M are letters.

[Y_Y]

Symbols like that can represent all sorts of things, and numbers are no exception! In fact the Romans had been using other letters to represent their numbers since Etruscan times. Wait until you hear the torrid history of the character V (and its "misrepresentation" U).