[MR] Roman Numerals

[jbrmm266 at aol.com]

The Middle Ages used Roman numerals quite a bit, though they were not universal.  

We use them in the SCA to show progressions (such as wars or other annual events), successive reigns by the same people, and usually our AS dates. 

AS stands for Anno Societatis, Latin for Year of the Society.  It changes in May, reflecting the founding of the SCA.  The fact that AS and CE (current era) dates are a bit out of phase sometimes causes confusion in reckoning dates.  The current year is AS 44, which started in May of 2009 and will change at the end of April 2010.

This is a link to a chart showing the relationship between AS and CE dates:  http://sca.org/links/calendar.html

Like many other ancient cultures, the Romans used letters to represent numbers.  However, their numerical value did not correspond with their alphabetic position.  The values assigned to the letters used for numbers are:

I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1000

For most values, you just put together the elements to add up to the value you need:

III = 3
VII = 7
XXII = 22
LXX = 70

What can get confusing is the custom of how to make the quantity just below the value of the next symbol.  You do it by putting a smaller number to the LEFT of a larger number.  This SUBTRACTS the value of the smaller from the larger, e.g.,

IV = 4 (5 - 1)*
IX = 9 (10 - 1)
XL = 40 (50 - 10)
XC = 90 (100 - 10)
CM = 900 (1000 - 100)

But it isn't used in every case.  You only use the I to subtract from V or X, not any of the higher numbers. For instance, 999 could theoretically be written as IM (1000 - 1) but it's CMXCIX (900 [CM] + 90 [XC] + 9 [IX]).  And 99 is not IC but XCIX.  

And as far as I know, they didn't use V to subtract from a higher number.
And those get stacked along with the rest of the number to make the total, e.g.,

XLIV = 44 (the current AS year) 
 
For a society that valued engineering, the Romans sure used an awkward way to reckon numbers!

When you see the closing credits of a movie, they almost always show the year in Roman numerals, which are almost impossible to read quickly:

MCMLXXVII = 1977 (M = 1000, CM = 900 [1000-100], LXX = 70 [50+10+10], VII = 7 [5+1+1]

MCMXXXIX = 1939 (M = 1000, CM = 900, XXX = 30 [10+10+10], IX = 9 [10-1]

Until you hit the milennium: MM = 2000.

The current CE year is written MMIX.

I hope this is of use to those not familiar with Roman numerals.

Your servant aye
Donal Mac Ruiseart.


*the 4 on a clock face is written IIII to avoid confusion with the 6 value at the bottom (because the 4 would be upside down) and to visually balance the VIII (8) opposite it on the clock face.