Roman Numerals

Roman numerals are a non-positional system of writing numbers with Latin letter signs: I, V, X, L, C, D and M. The system developed in ancient Italy and was used in inscriptions, documents, calendars, legion names, monuments, coins and architectural elements.

In brief:

• I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000;
• numbers are usually read from left to right, from larger signs to smaller ones;
• a smaller sign before a larger one can be subtracted: IV = 4, IX = 9, XL = 40;
• the Romans had no separate sign for zero;
• ancient usage was less standardized than the modern school system.

Table of Roman numerals

Basic signs:

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

Examples:

• II = 2
• III = 3
• IV = 4
• VIII = 8
• IX = 9
• XII = 12
• XL = 40
• XC = 90
• CD = 400
• CM = 900
• MMXXVI = 2026

Writing rules

Modern school notation combines addition and subtraction. If a smaller or equal sign follows a larger sign, it is added: VI = 6, XV = 15, LX = 60. If a smaller sign stands before a larger sign, it is subtracted: IV = 4, IX = 9, XL = 40, XC = 90.

Normally I, X, C and M may be repeated up to three times in a row: III = 3, XXX = 30, CCC = 300. V, L and D are not repeated. In the modern standard, subtraction is limited: I is placed before V and X, X before L and C, C before D and M. Therefore 49 is written XLIX, not IL.

Ancient practice was more flexible. Roman inscriptions may show forms such as IIII instead of IV, especially on clocks, building marks and some epigraphic monuments. When reading an ancient inscription, context matters as much as modern classroom rules.

How to read dates

Roman numerals often appear in dates, monuments and regnal names. A convenient way to read a number is to split it into parts:

• MMXXVI = MM + XX + VI = 2000 + 20 + 6 = 2026;
• CDLXXVI = CD + LXX + VI = 400 + 70 + 6 = 476;
• DCCLIII = D + CC + L + III = 753;
• XLIV = XL + IV = 44.

If the date refers to an event BCE, the numeral itself does not change: XLIV BCE means 44 BCE. It is important to remember that in the traditional year count there is no year zero between 1 BCE and 1 CE.

Where Romans used numerals

Roman numerals appeared in official and everyday contexts. They were used for years, ordinal numbers, sums, military units, book chapters, monument inscriptions, building marks and records. On military monuments the numbers of legions are especially important: for example, Legio X, Legio XIII or Legio XXII.

In everyday calculation, Romans did not rely only on written notation. They used fingers, counting boards, pebbles and abaci. Roman numerals were useful for recording a result, but they were not as convenient for written multiplication or division as a positional decimal system.

Large numbers and variants

For numbers above one thousand, Romans could repeat M or use special devices. In later and medieval practice, a bar above a numeral could multiply it by one thousand: V with an overbar meant 5,000, X with an overbar meant 10,000. Epigraphy also preserves local and professional variants, so the same value may not always be written exactly as in modern tables.

This matters for reenactors and readers of inscriptions: the "correct" form depends on date, place and genre of the source. For modern reference it is convenient to use the normalized system, but when working with an original monument it is better to preserve the actual form of the inscription.

Topic navigation

I. Rome and written culture

• Ancient Rome
• Antiquity
• Wax tablet
• Tessera

II. Inscriptions and monuments

• Roman streets
• Roman temples
• Trajan's Column
• Roman Forum

III. Where numbers appear

• List of Roman legions
• Legion
• Roman army
• Roman names

Literature

1. Georges Ifrah. The Universal History of Numbers. 2. Karl Menninger. Number Words and Number Symbols. 3. Graham Flegg. Numbers: Their History and Meaning. 4. Gordon, Arthur E. Illustrated Introduction to Latin Epigraphy. 5. Oxford Classical Dictionary. Numerals; Epigraphy.

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