Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers are written with combinations of letters from the Latin alphabet, each with a fixed integer value. The modern style uses only these seven:
1 | 5 | 10 | 50 | 100 | 500 | 1000 |
The use of Roman numerals continued long after the decline of the Roman Empire. From the 14th century on, Roman numerals began to be replaced by Arabic numerals; however, this process was gradual, and the use of Roman numerals persisted in various places, including on clock face. For instance, on the clock of Big Ben (designed in 1852), the hours from 1 to 12 are written as:
The notations and can be read as "one less than five" (4) and "one less than ten" (9), although there is a tradition favouring the representation of "4" as "" on Roman numeral clocks.
Other common uses include year numbers on monuments and buildings and copyright dates on the title screens of films and television programmes. , signifying "a thousand, and a hundred less than another thousand", means 1900, so 1912 is written . For the years of the current (21st) century, indicates 2000; this year is (2025).
This allows some flexibility in notation, and there has never been an official or universally accepted standard for Roman numerals. Usage varied greatly in ancient Rome and became thoroughly chaotic in medieval times. The more recent restoration of a largely "classical" notation has gained popularity among some, while variant forms are used by some modern writers as seeking more "flexibility". Roman numerals may be considered legally binding expressions of a number, as in U.S. copyright law before the Berne Convention Implementation Act of 1988 (where an "incorrect" or ambiguous numeral in a copyright notice could invalidate a copyright claim or affect the termination date of the copyright period).
+ Individual decimal places |
The numerals for 4 () and 9 () are written using subtractive notation, 288 pages. where the smaller symbol () is ''subtracted'' from the larger one (, or ), thus avoiding the clumsier and . Subtractive notation is also used for 40 (), 90 (), 400 () and 900 (). 546 pages. These are the only subtractive forms in standard use.
A number containing two or more decimal digits is built by appending the Roman numeral equivalent for each, from highest to lowest, as in the following examples:
Any missing place (represented by a zero in the place-value equivalent) is omitted, as in Latin (and English) speech:
The largest number that can be represented in this manner is 3,999 ( ), but this is sufficient for the values for which Roman numerals are commonly used today, such as year numbers:
For larger numbers (4,000 and larger): Both before and after the introduction of Arabic numerals in the West, from ancient times through medieval and modern, users of Roman numerals have used various means to write larger numbers .
The two conventions could be mixed in the same document or inscription, even in the same numeral. For example, on the numbered gates to the Colosseum, is systematically used instead of , but subtractive notation is used for ; consequently, gate 44 is labelled .
Especially on tombstones and other funerary inscriptions, 5 and 50 have been occasionally written and instead of and , and there are instances such as and rather than or .
Modern that use Roman numerals still very often use for four o'clock but for nine o'clock, a practice that goes back to very early clocks such as the Wells Cathedral clock of the late 14th century. However, this is far from universal: for example, the clock on the Palace of Westminster tower (commonly known as Big Ben) uses a subtractive for 4 o'clock.
Several monumental inscriptions created in the early 20th century use variant forms for "1900" (usually written ). These vary from for 1910 as seen on Admiralty Arch, London, to the more unusual, if not unique for 1903, on the north entrance to the Saint Louis Art Museum.
The function in Microsoft Excel supports multiple subtraction modes depending on the "" setting. For example, the number "499" (usually ) can be rendered as , , or . The relevant Microsoft help page offers no explanation for this function other than to describe its output as "more concise".
The use of to indicate "none" long survived in the historic apothecaries' system of measurement: used well into the 20th century to designate quantities in pharmaceutical prescriptions.
In later times, the Arabic numeral "0" has been used as a zero to open enumerations with Roman numbers. Examples include the 24-hour Shepherd Gate Clock from 1852 and tarot packs such as the 15th-century Sola Busca and the 20th century Rider–Waite packs.
The Romans used a duodecimal rather than a decimal system for rational number, as the divisibility of twelve makes it easier to handle the common fractions of and than does a system based on ten . Notation for fractions other than is mainly found on surviving , many of which had values that were duodecimal fractions of the unit as. Fractions less than are indicated by a dot ( ·) for each uncia "twelfth", the source of the English words inch and ounce; dots are repeated for fractions up to five twelfths. Six twelfths (one half), is for semis "half". Uncia dots were added to for fractions from seven to eleven twelfths, just as tallies were added to for whole numbers from six to nine. The arrangement of the dots was variable and not necessarily Linearity. Five dots arranged like ( ⁙) (as on the face of a dice) are known as a quincunx, from the name of the Roman fraction/coin. The Latin words sextans and quadrans are the source of the English words sextant and quadrant.
Each fraction from to had a name in Roman times; these corresponded to the names of the related coins:
· | Uncia, unciae | "Ounce" | |
= | ·· or : | Sextans, sextantis | "Sixth" |
= | ··· or ∴ | Quadrans, quadrantis | "Quarter" |
= | ···· or ∷ | Triens, trientis | "Third" |
····· or ⁙ | Quincunx, quincuncis | "Five-ounce" (quinque unciae → quincunx) | |
= | Semis, semissis | "Half" | |
· | Septunx, septuncis | "Seven-ounce" (septem unciae → septunx) | |
= | ·· or : | Bes, bessis | "Twice" (as in "twice a third") |
= | ··· or ∴ | Dodrans, dodrantis or nonuncium, nonuncii | "Less a quarter" (de-quadrans → dodrans) or "ninth ounce" (nona uncia → nonuncium) |
= | ···· or ∷ | Dextans, dextantis or decunx, decuncis | "Less a sixth" (de-sextans → dextans) or "ten ounces" (decem unciae → decunx) |
····· or ⁙ | Deunx, deuncis | "Less an ounce" (de-uncia → deunx) | |
= 1 | As, assis | "Unit" |
Other Roman fractional notations included the following:
=12−3 | Siliqua, siliquae | ||
Scripulum, scripuli | "scruple" | ||
=12−2 | Dimidia sextula, dimidiae sextulae | "half a sextula" | |
Sextula, sextulae | " of an uncia" | ||
Sicilicus, sicilici | |||
Binae sextulae, binarum sextularum (Exceptionally, these are plural forms.) | "two sextulas" (duella, duellae) | ||
or or | Semuncia, semunciae | " uncia" (semi- + uncia) | |
· or · or · | Sescuncia, sescunciae | " uncias" (Numeral prefix]]- + uncia) |
Fractions could also be indicated with a slash through the last letter in a numeral (e.g. ), which subtracted the number by an amount less than one (usually ).
Each additional set of and surrounding raises the value by a factor of ten: represents 10,000 and represents 100,000. Similarly, each additional to the right of raises the value by a factor of ten: represents 5,000 and represents 50,000. Numerals larger than do not occur.
Sometimes (1000) is reduced to , (5,000) to ; (10,000) to ; (50,000) to ; and (100,000) to . It is likely (500) reduced to and (1000) influenced the later .
John Wallis is often credited with introducing the symbol for infinity , and one conjecture is that he based it on , since 1,000 was hyperbole used to represent very large numbers.
An overline can be typed to represent this notation, such that X̄ denotes ten thousand, C̄ denotes a hundred thousand, and M̄ denotes a million.
The vinculum came into use in the Roman Republic,
In an extension of the vinculum, a three-sided box (now sometimes printed as two vertical lines and a vinculum) is used to multiply by 100,000, thus:
Vinculum notation is distinct from the custom of adding an overline to a numeral simply to indicate that it is a number. Both usages can be seen on Roman inscriptions of the same period and general location, such as on the Antonine Wall.
The Roman numerals, in particular, are directly derived from the Etruscan number symbols: , , , , and for 1, 5, 10, 50, and 100 (they had more symbols for larger numbers, but it is unknown which symbol represents which number). As in the basic Roman system, the Etruscans wrote the symbols that added to the desired number, from higher to lower value. Thus, the number 87, for example, would be written 50 + 10 + 10 + 10 + 5 + 1 + 1 = 𐌣𐌢𐌢𐌢𐌡𐌠𐌠 (this would appear as 𐌠𐌠𐌡𐌢𐌢𐌢𐌣 since Etruscan was written from right to left.)
The symbols and resembled letters of the Etruscan alphabet, but , , and did not. The Etruscans used the subtractive notation, too, but not like the Romans. They wrote 17, 18, and 19 as 𐌠𐌠𐌠𐌢𐌢, 𐌠𐌠𐌢𐌢, and 𐌠𐌢𐌢, mirroring the way they spoke those numbers ("three from twenty", etc.); and similarly for 27, 28, 29, 37, 38, etc. However, they did not write 𐌠𐌡 for 4 (nor 𐌢𐌣 for 40), and wrote 𐌡𐌠𐌠, 𐌡𐌠𐌠𐌠 and 𐌡𐌠𐌠𐌠𐌠 for 7, 8, and 9, respectively.
The symbol for 100 was written variously as or , and was then abbreviated to or , with (which matched the Latin letter C) finally winning out. It might have helped that C was the initial letter of CENTUM, Latin for "hundred".
The numbers 500 and 1000 were denoted by or overlaid with a box or circle. Thus, 500 was like a superimposed on a or , making it look like . It became or by the time of Augustus, under the graphic influence of the letter . It was later identified as the letter ; an alternative symbol for "thousand" was a , and half of a thousand or "five hundred" is the right half of the symbol, , and this may have been converted into .
The notation for 1000 was a circled or boxed : Ⓧ, , , and by Augustan times was partially identified with the Greek letter phi. Over time, the symbol changed to and . The latter symbol further evolved into , then , and eventually changed to under the influence of the Latin word mille "thousand".
According to Paul Kayser, the basic numerical symbols were , , and (or ) and the intermediate ones were derived by taking half of those (half an is , half a is and half a is ). Then 𐌟 and ↆ developed as mentioned above.
Since the Middle Ages, a "" has sometimes been substituted for the final "" of a "lower-case" Roman numeral, such as "" for 3 or "" for 7. This "" can be considered a swash variant of "". Into the early 20th century, the use of a final "" was still sometimes used in medical prescriptions to prevent tampering with or misinterpretation of a number after it was written.Bastedo, Walter A. Materia Medica: Pharmacology, Therapeutics and Prescription Writing for Students and Practitioners, 2nd ed. (Philadelphia, PA: W.B. Saunders, 1919) p582. Retrieved 15 March 2010.
Numerals in documents and inscriptions from the Middle Ages sometimes include additional symbols, which today are called "medieval Roman numerals". Some simply substitute another letter for the standard one (such as "" for "", or "" for ""), while others serve as abbreviations for compound numerals ("" for "", or "" for ""). Although they are still listed today in some dictionaries, they are long out of use.
A superscript "o" (sometimes written directly above the symbol) was sometimes used as an ordinal indicator.
, messages with dates encoded into them, were popular during the Renaissance era. The chronogram would be a phrase containing the letters , , , , , , and . By putting these letters together, the reader would obtain a number, usually indicating a particular year.
In astronomy, the natural satellites or "moons" of the are designated by capital Roman numerals appended to the planet's name. For example, Titan's designation is Saturn .
In chemistry, Roman numerals are sometimes used to denote the groups of the periodic table, but this has officially been deprecated in favour of Arabic numerals. They are also used in the IUPAC nomenclature of inorganic chemistry, for the oxidation number of which can take on several different positive charges. They are also used for naming phases of polymorphic , such as ice.
In education, school grades (in the sense of year-groups rather than test scores) are sometimes referred to by a Roman numeral; for example, "grade " is sometimes seen for "grade 9".
In entomology, the broods of the thirteen- and seventeen-year periodical cicadas are identified by Roman numerals.
In graphic design, stylised Roman numerals may represent numeric values.
In law, Roman numerals are commonly used to help organize legal codes as part of an alphanumeric outline.
In mathematics (including trigonometry, statistics, and calculus), when a graph includes negative numbers, its quadrants are named using , , , and . These quadrant names signify positive numbers on both axes, negative numbers on the x-axis, negative numbers on both axes, and negative numbers on the y-axis, respectively. The use of Roman numerals to designate quadrants avoids confusion, since Arabic numerals are used for the actual data represented in the graph.
In military unit designation, Roman numerals are often used to distinguish between units at different levels. This reduces possible confusion, especially when viewing operational or strategic level maps. In particular, army corps are often numbered using Roman numerals (for example, the American XVIII Airborne Corps or the Nazi III Panzerkorps) with Arabic numerals being used for divisions and armies.
In music, Roman numerals are used in several contexts:
In pharmacy, Roman numerals were used with the now largely obsolete apothecaries' system of measurement: including to denote "one half" and to denote "zero".
In photography, Roman numerals (with zero) are used to denote varying levels of brightness when using the Zone System.
In seismology, Roman numerals are used to designate degrees of the Mercalli intensity scale of earthquakes.
In team sport the team containing the "top" players and representing a nation or province, a Sports club or a school at the highest level in (say) rugby union is often called the "1st ", while a lower-ranking cricket or American football team might be the "3rd ".
In tarot, Roman numerals (with zero) are often used to denote the cards of the Major Arcana.
In Ireland, Roman numerals were used until the late 1980s to indicate the month on postage Franking. In documents, Roman numerals are sometimes still used to indicate the month to avoid confusion over day/month/year or month/day/year formats.
In theology and biblical scholarship, the Septuagint is often referred to as , as this translation of the Old Testament into Greek is named for the legendary number of its translators ( septuaginta being Latin for "seventy").
Capital or Small caps Roman numerals are widely used in Romance languages to denote , e.g. the French xviiie siècle
Mixed Roman and Arabic numerals are sometimes used in numeric representations of dates (especially in formal letters and official documents, but also on tombstones). The is written in Roman numerals, while the day is in Arabic numerals: "4..1789" and ".4.1789" both refer unambiguously to 4 June 1789.
Roman numerals are sometimes used to represent the in hours-of-operation signs displayed in windows or on doors of businesses, and sometimes in railway and bus timetables. Monday, taken as the first day of the week, is represented by . Sunday is represented by . The hours of operation signs are tables composed of two columns where the left column is the day of the week in Roman numerals and the right column is a range of hours of operation from starting time to closing time. In the example case (left), the business opens from 10 AM to 7 PM on weekdays, 10 AM to 5 PM on Saturdays and is Sunday shopping. Note that the listing uses 24-hour time.
Roman numerals may also be used for floor numbering. For instance, apartments in central Amsterdam are indicated as 138-, with both an Arabic numeral (number of the block or house) and a Roman numeral (floor number). The apartment on the ground floor is indicated as 138-huis.
In Italy, where roads outside built-up areas have Milestone, major roads and motorways also mark 100-metre subdivisionals, using Roman numerals from to for the smaller intervals. The sign thus marks 17.9 km.
Certain romance-speaking countries use Roman numerals to designate assemblies of their national legislatures. For instance, the composition of the Italy Parliament from 2018 to 2022 (elected in the 2018 Italian general election) is called the XVIII Legislature of the Italian Republic (or more commonly the "XVIII Legislature").
A notable exception to the use of Roman numerals in Europe is in Greece, where Greek numerals (based on the Greek alphabet) are generally used in contexts where Roman numerals would be used elsewhere.
Large numbers
Apostrophus
Vinculum
Other
Page 347: Lettre de Philippe le Beau aux échevins..., quote: "Escript en nostre ville de Gand, le XXIIIIme de febvrier, l'an IIIIXXXIX quatre-vingt-dix-neuf."
Page 356: Lettre de l'achiduchesse Marguerite au conseil de Brabant..., quote: "... Escript à Bruxelles, le dernier jour de juing anno XVcXIX 1519."
Page 374: Letters patentes de la rémission ... de la ville de Bruxelles, quote: "... Op heden, tweentwintich 'twenty-two' daegen in decembri, anno vyfthien hondert tweendertich 'fifteen ... Gegeven op ten vyfsten dach in deser jegewoirdige maent van decembri anno XV tweendertich 1532 vorschreven."
Page 419: Acte du duc de Parme portant approbation..., quote: "Faiet le XVme de juillet XVc huytante-six 1586.".
Origin
Etruscan numerals
Early Roman numerals
Classical Roman numerals
Use in the Middle Ages and Renaissance
5 Resembles an upside-down V. Also said to equal 500. 6 ↅ Either from a ligature of , or from digamma (ϛ), the Greek numeral 6 (sometimes conflated with the στ ligature).. 7 , Presumed abbreviation of septem, Latin for 7. 11 Presumed abbreviation of onze, French for 11. 40 Presumed abbreviation of English forty. 70 Also could stand for 7, with the same derivation. 80 90 Presumed abbreviation of nonaginta, Latin for 90. (Ambiguous with for "nothing" ( nihil)). 150 Possibly derived from the lowercase y's shape. 151 Unusual, origin unknown; also said to stand for 250. 160 Possibly derived from Greek tetra, as 4 × 40 = 160. 200 Could also stand for 2 (see also 𐆙, the symbol for the dupondius). From a barring of two 's. 250 300 400 , 500 Redundant with ; abbreviates quingenti, Latin for 500. Also sometimes used for 500,000. 800 Borrowed from Gothic alphabet. 900 Borrowed from Gothic. 2000 9000 Cappelli notes that the T with double dot is only attested for Spanish-suited playing cards.
Modern use
Specific disciplines
Modern use in European languages other than English
Unicode
See also
Notes
Citations
Sources
Further reading
External links
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