# Interpreting Roman Numerals

A Refresher Course

*Roman numerals helped kill the Roman Empire; now they're killing us.*

Genealogists encounter Roman numerals in dates and in pagination. This review will cover only Roman numerals less than
**MMM** (3,000.)

**MDCCCLXXXVI**

What does it mean?

There are seven letters used in modern Roman numerals:

## For numbers less that 3,000

I |
means | 1 |

V |
means | 5 |

X |
means | 10 |

L |
means | 50 |

C |
means | 100 |

D |
means | 500 |

M |
means | 1000 |

Some Roman numerals can be doubled, tripled, or quadrupled.

XX |
means | 20 |

XXX |
means | 30 |

CC |
means | 200 |

MM |
means | 2,000 |

Sometimes lower case letters are used for pagination: **i**,
**v**, **x**, **l**, **c**,
**d**, and **m**.

Fragments of the Roman system of numerals survive in modern times, as in the expression "**C** note" meaning a one hundred dollar bill.

*Roman numerals are sometimes used on modern banknotes. The obverse of this ten dollar note has a border of Xs, the Roman numeral for ten, and a prominant X is displayed on the reverse where the field is filled with Xs.*

*The Roman numeral XX is prominently displayed on the obverse of this twenty dollar banknote.*

### The Subtraction Rule

If you use the charts below, you will not have to remember the rule

There is only one rule to remember, and that is that identical letters are only repeated three times in succession. To avoid four identical letters in succession, subtraction is used. The rule for subtraction is that if a letter is preceeded by a letter with a lesser value, the first is subtracted from the second.

IV |
means | 4 |
(5-1=4) |

IX |
means | 9 |
(10-1=9) |

XL |
means | 40 |
(50-10=40) |

XC |
means | 90 |
(100-10=90) |

CD |
means | 400 |
(500-100=400) |

CM |
means | 900 |
(1000-100=900) |

For example, to translate the Roman numeral **XXXIII**, find it on the chart (green). The translation is the sum of Arabic numeral at the top of the column, 30 (blue), and the Arabic numeral at the left of the row, 3 (red).
**XXXIII** means **33**. Notice that there is no Roman numeral for the value zero.

Sometimes this rule was not followed, so you will see four letters repeated in succession, such as
**IIII** for four or **MCCCC** for one thousand four hundred.

## Numerals 1 to 99

*caption text*

## Numerals 100 to 2,999

To create numbers in the 101 to 2,999, concatenate the following letters with the appropriate letters from the chart above.

*Roman numeral 100s*

## Examples Converting from Roman to Arabic Numerals

**DCCCLXIX**

DCCC LX IX (break into levels of 1000s, 100s, 10s, and 1s)

*DCCC means 800
LX means 60
IX means 9
800+60+9=*

**869**

**CMLXIV**

*CM LX IV (break into levels of 1000s, 100s, 10s, and 1s)
CM means 900
LX means 60
IV means 4
900+60+4=*

**964**

On the title page of a book is given the date **MDCCCLXXXVI**

*M DCCC LXXX VI (break into levels of 1000s, 100s, 10s, and 1s)
M means 1,000
DCCC means 800
LXXX means 80
VI means 6
1,000+800+80+6=*

**1,886**or the year 1886

## Converting from Arabic to Roman Numerals

To convert from Arabic to Roman numerals, follow the same process in raverse order.