The set of Roman numerals used for writing calendar dates
1 = I (one); 5 = V (five);
10 = X (ten); 50 = L (fifty);
100 = C (one hundred); 500 = D (five hundred);
1,000 = M (one thousand);
(*) 5,000 = (V) (five thousand); (*) 10,000 = (X) (ten thousand) - for writing dates in the future;
Note 1: (*) Number was also written with a bar above or between two vertical bars. We prefer this kind of writing of larger numerals between brackets "()" since it's more accessible to computer users and on the other hand it avoids the confusion between the vertical bar "|" and the Roman numeral of "I" (I = one).
Note 2: (*) Romans did not use right from the beginning numbers larger than 3,999, so they initially had no representation for numbers like:
- 5,000 = (V), 10,000 = (X), 50,000 = (L), 100,000 = (C), 500,000 = (D), or 1,000,000 = (M).
These larger numerals were added later to the system and various different notations were used for them, not necessarily the ones above.
For a long time, the maximum number that could be written using Roman numerals was:
- MMMCMXCIX = 3,999.