Roman numerals

File:Year 1575 in Arabic and Roman numbers.jpg

Year 1575 in Arabic and Roman numbers

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:

Template:Rn	Template:Rn	Template:Rn	Template:Rn	Template:Rn	Template:Rn	Template:Rn
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 faces. For instance, on the clock of Big Ben (designed in 1852), the hours from 1 to 12 are written as:

The notations Template:Rn and Template:Rn 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 "Template:Rn" 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. Template:Rn, signifying "a thousand, and a hundred less than another thousand", means 1900, so 1912 is written Template:Rn. For the years of the current (Template:Ordinal) century, Template:Rn indicates 2000; this year is Template:Rn (2025).

Description

File:CuttySarkRomNum.jpg

Roman numerals on stern of the ship showing draught in feet. The numbers range from 13 to 22, from bottom to top.

Roman numerals use different symbols for each power of ten, and there is no zero symbol, in contrast with the place value notation of Arabic numerals (in which place-keeping zeros enable the same digit to represent different powers of ten).

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).

Standard form

The following table displays how Roman numerals are usually written in modern times:

Individual decimal places

	Thousands	Hundreds	Tens	Units
1	Template:Rn	Template:Rn	Template:Rn	Template:Rn
2	Template:Rn	Template:Rn	Template:Rn	Template:Rn
3	Template:Rn	Template:Rn	Template:Rn	Template:Rn
4		Template:Rn	Template:Rn	Template:Rn
5		Template:Rn	Template:Rn	Template:Rn
6		Template:Rn	Template:Rn	Template:Rn
7		Template:Rn	Template:Rn	Template:Rn
8		Template:Rn	Template:Rn	Template:Rn
9		Template:Rn	Template:Rn	Template:Rn

The numerals for 4 (Template:Rn) and 9 (Template:Rn) are written using subtractive notation, where the smaller symbol (Template:Rn) is subtracted from the larger one (Template:Rn or Template:Rn), instead of Template:Rn and Template:Rn.Template:Efn Subtractive notation is also used for 40 (Template:Rn), 90 (Template:Rn), 400 (Template:Rn) and 900 (Template:Rn). 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:

• 39 = Template:Rn + Template:Rn = Template:Rn.
• 246 = Template:Rn + Template:Rn + Template:Rn = Template:Rn.
• 789 = Template:Rn + Template:Rn + Template:Rn = Template:Rn.
• 2,421 = Template:Rn + Template:Rn + Template:Rn + Template:Rn = Template:Rn.

Any missing place (represented by a zero in the place-value equivalent) is omitted, as in Latin (and English) speech:

• 160 = Template:Rn + Template:Rn = Template:Rn
• 207 = Template:Rn + Template:Rn = Template:Rn
• 1,009 = Template:Rn + Template:Rn = Template:Rn
• 1,066 = Template:Rn + Template:Rn + Template:Rn = Template:Rn

The largest number that can be represented in this manner is 3,999 (Template:Rn), but this is sufficient for the values for which Roman numerals are commonly used today, such as year numbers:

• 1776 = Template:Rn + Template:Rn + Template:Rn + Template:Rn = Template:Rn (the date written on the book held by the Statue of Liberty).
• 1918 = Template:Rn + Template:Rn + Template:Rn + Template:Rn = Template:Rn (the first year of the Spanish flu pandemic)
• 1944 = Template:Rn + Template:Rn + Template:Rn + Template:Rn = Template:Rn (erroneous copyright notice of the 1954 movie The Last Time I Saw Paris)
• 2025 = Template:Rn (this year)Template:Efn

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 Template:Xref.

Other forms

Forms exist that vary in one way or another from the general standard represented above.

Other additive forms

File:BadSalzdetfurthBadenburgerStr060529.jpg

A clock face with the Roman numerals typical for clocks, in Bad Salzdetfurth, Germany

While subtractive notation for 4, 40, and 400 (Template:Rn, Template:Rn, and Template:Rn) has been the usual form since Roman times , additive notation to represent these numbers (Template:Rn, Template:Rn, and Template:Rn) very frequently continued to be used, including in compound numbers like 24 (Template:Rn), 74 (Template:Rn), and 490 (Template:Rn). The additive forms for 9, 90, and 900 (Template:Rn, Template:Rn, and Template:Rn) have also been used, although less often.

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, Template:Rn is systematically used instead of Template:Rn, but subtractive notation is used for Template:Rn; consequently, gate 44 is labelled Template:Rn.

Especially on tombstones and other funerary inscriptions, 5 and 50 have been occasionally written Template:Rn and Template:Rn instead of Template:Rn and Template:Rn, and there are instances such as Template:Rn and Template:Rn rather than Template:Rn or Template:Rn.

Modern clock faces that use Roman numerals still very often use Template:Rn for four o'clock but Template:Rn 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 Template:Rn for 4 o'clock.Template:Efn

File:AdmiraltyArchLondonCloseup.jpg

The year number on Admiralty Arch, London. The year 1910 is rendered as Template:Rn, rather than the more usual Template:Rn

Several monumental inscriptions created in the early 20th century use variant forms for "1900" (usually written Template:Rn). These vary from Template:Rn for 1910 as seen on Admiralty Arch, London, to the more unusual, if not unique Template:Rn for 1903, on the north entrance to the Saint Louis Art Museum.

File:Epitaph des Marcus Caelius.JPG

Epitaph of centurion Marcus Caelius, showing "Template:Rn"

Other subtractive forms

There are numerous historical examples of Template:Rn being used for 8; for example, Template:Rn was used by officers of the XVIII Roman Legion to write their number. The notation appears prominently on the cenotaph of their senior centurion Marcus Caelius (Template:Circa – 9 AD). On the publicly displayed official Roman calendars known as Fasti, Template:Rn is used for the 18 days to the next Kalends, and Template:Rn for the 28 days in February. The latter can be seen on the sole extant pre-Julian calendar, the Fasti Antiates Maiores. There are historical examples of other subtractive forms: Template:Rn for 17, Template:Rn for 18, Template:Rn for 97, Template:Rn for 98, and Template:Rn for 99. A possible explanation is that the word for 18 in Latin is Template:Px2Template:MdashTemplate:Tspliterally "two from twenty"⁠Template:MdashTemplate:Tspwhile 98 is (two from hundred) and 99 is (one from hundred). However, the explanation does not seem to apply to Template:Rn and Template:Rn, since the Latin words for 17 and 97 were (seven ten) and (ninety seven), respectively.

The ROMAN() function in Microsoft Excel supports multiple subtraction modes depending on the "Template:Tt" setting. For example, the number "499" (usually Template:Rn) can be rendered as Template:Rn ((500-50)+(50-5)+(5-1)), Template:Rn ((500-10)+(10-1)), Template:Rn ((500-5)+(5-1)) or Template:Rn (500-1). The relevant Microsoft help page offers no explanation for this function other than to describe its output as "more concise".

Non-standard variants

File:Padlock, Athlone.jpg

Padlock used on the north gate of the Irish town of Athlone. "1613" in the date is rendered Template:Rn, (literally "16, 13") instead of Template:Rn.

File:Excerpt from BnF ms. 1433 fr., fol. 24r.png

Excerpt from Bibliothèque nationale de France. The Roman numeral for 500 is rendered as Template:Rn, instead of Template:Rn.

There are also historical examples of other additive and multiplicative forms, and forms which seem to reflect spoken phrases. Some of these variants may have been regarded as errors even by contemporaries.

• Template:Rn was how people associated with the XXII Roman Legion used to write their number. The practice may have been due to a common way to say "twenty-second" in Latin, namely (literally "two and twentieth") rather than the "regular" (twenty second). Apparently, at least one ancient stonecutter mistakenly thought that the Template:Rn of "22nd Legion" stood for 18, and "corrected" it to Template:Rn.

• Other numerals that do not fit the usual patterns – such as Template:Rn for 45, instead of the usual Template:Rn — may be due to scribal errors, or the writer's lack of familiarity with the system, rather than being genuine variant usage.

Non-numeric combinations

As Roman numerals are composed of ordinary alphabetic characters, there may sometimes be confusion with other uses of the same letters. For example, "XXX" and "XL" have other connotations in addition to their values as Roman numerals, while "IXL" more often than not is a gramogram of "I excel", and is in any case not an unambiguous Roman numeral.

Zero

As a non-positional numeral system, Roman numerals have no "place-keeping" zeros. Furthermore, the system as used by the Romans lacked a numeral for the number zero itself (that is, what remains after 1 is subtracted from 1). The word Template:Wikt-lang (the Latin word meaning "none") was used to represent 0, although the earliest attested instances are medieval. For instance Dionysius Exiguus used alongside Roman numerals in a manuscript from 525 AD. About 725, Bede or one of his colleagues used the letter Template:Rn, the initial of or of Template:Wikt-lang (the Latin word for "nothing") for 0, in a table of epacts, all written in Roman numerals.

The use of Template:Rn 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.

Fractions

File:Vecchi 003.jpg

A coin (1⁄3 or 4⁄12 of an ). Note the four dots (····) indicating its value.

File:Semisse.jpg

A coin (1⁄2 or 6⁄12 of an ). Note the Template:Rn indicating its value.

The base "Roman fraction" is Template:Rn, indicating 1⁄2. The use of Template:Rn (as in Template:Rn to indicate 7+1⁄2) is attested in some ancient inscriptions and in the now rare apothecaries' system (usually in the form Template:Rn): but while Roman numerals for whole numbers are essentially decimal, Template:Rn does not correspond to 5⁄10, as one might expect, but 6⁄12.

The Romans used a duodecimal rather than a decimal system for fractions, as the divisibility of twelve (12 = 2² × 3) makes it easier to handle the common fractions of 1⁄3 and 1⁄4 than does a system based on ten (10 = 2 × 5). Notation for fractions other than 1⁄2 is mainly found on surviving Roman coins, many of which had values that were duodecimal fractions of the unit . Fractions less than 1⁄2 are indicated by a dot (·) for each "twelfth", the source of the English words inch and ounce; dots are repeated for fractions up to five twelfths. Six twelfths (one half), is Template:Rn for "half". Uncia dots were added to Template:Rn for fractions from seven to eleven twelfths, just as tallies were added to Template:Rn for whole numbers from six to nine. The arrangement of the dots was variable and not necessarily linear. Five dots arranged like (⁙) (as on the face of a die) are known as a quincunx, from the name of the Roman fraction/coin. The Latin words and are the source of the English words sextant and quadrant.

Each fraction from 1⁄12 to 12⁄12 had a name in Roman times; these corresponded to the names of the related coins:

Fraction	Roman numeral	Name (nominative and genitive singular)	Meaning
1⁄12	·		"Ounce"
2⁄12 = 1⁄6	·· or :		"Sixth"
3⁄12 = 1⁄4	··· or ∴		"Quarter"
4⁄12 = 1⁄3	···· or ∷		"Third"
5⁄12	····· or ⁙		"Five-ounce" ( → )
6⁄12 = 1⁄2	Template:Rn		"Half"
7⁄12	Template:Rn·		"Seven-ounce" ( → )
8⁄12 = 2⁄3	Template:Rn·· or Template:Rn:		"Twice" (as in "twice a third")
9⁄12 = 3⁄4	Template:Rn··· or Template:Rn∴	or	"Less a quarter" ( → ) or "ninth ounce" ( → )
10⁄12 = 5⁄6	Template:Rn···· or Template:Rn∷	or	"Less a sixth" ( → ) or "ten ounces" ( → )
11⁄12	Template:Rn····· or Template:Rn⁙		"Less an ounce" ( → )
12⁄12 = 1	Template:Rn		"Unit"

Other Roman fractional notations included the following:

Fraction	Roman numeral	Name (nominative and genitive singular)	Meaning
1⁄1728=12−3	Template:Rn
1⁄288	Template:Rn		"scruple"
1⁄144=12−2	Template:Rn		"half a sextula"
1⁄72	Template:Rn		"1⁄6 of an uncia"
1⁄48	Template:Rn
1⁄36	Template:Rn	(Exceptionally, these are plural forms.)	"two sextulas" ()
1⁄24	Template:Rn or Template:Rn or Template:Rn		"1⁄2 uncia" ( + )
1⁄8	Template:Rn· or Template:Rn· or Template:Rn·		"1+1⁄2 uncias" ( + )

Fractions could also be indicated with a slash through the last letter in a numeral (e.g. Template:Rn), which subtracted the number by an amount less than one (usually 1⁄2).

Large numbers

The modern form can only write numbers up to 3999, and without M in early Roman times only numbers up to 899 could be written. Various schemes have been used over time to write larger numbers.

Apostrophus

File:Westerkerk MDCXXX.jpg

"1630" on the Westerkerk in Amsterdam. "Template:Rn" and "Template:Rn" are given archaic form.

Using the method, 500 is written as Template:Rn, while 1,000 is written as Template:Rn. This system of encasing numbers to denote thousands (imagine the Template:Rns and Template:Rns as parentheses) had its origins in Etruscan numeral usage.

Each additional set of Template:Rn and Template:Rn surrounding Template:Rn raises the value by a factor of ten: Template:Rn represents 10,000 and Template:Rn represents 100,000. Similarly, each additional Template:Rn to the right of Template:Rn raises the value by a factor of ten: Template:Rn represents 5,000 and Template:Rn represents 50,000. Numerals larger than Template:Rn do not occur.

File:Roman numerals Bungus 1584-1585.png

Page from a 16th-century manual, showing a mixture of and numbers (see in particular the ways of writing 10,000).

• Template:Rn = 500
• Template:Rn = 1,000
• Template:Rn = 5,000
• Template:Rn = 10,000
• Template:Rn = 50,000
• Template:Rn = 100,000

Sometimes Template:Rn (500) is reduced to Template:Rn, Template:Rn (1,000) to Template:Rn, Template:Rn (5,000) to Template:Rn; Template:Rn (10,000) to Template:Rn; Template:Rn (50,000) to Template:Rn; and Template:Rn (100,000) to Template:Rn. It is likely Template:Rn (1000) influenced the later Template:Rn.

John Wallis is often credited with introducing [[infinity symbol|the Template:Angbr symbol]] for infinity, and one conjecture is his basing it on Template:Rn, since 1,000 was hyperbolically used to represent very large numbers.

Vinculum

Using the , conventional Roman numerals are multiplied by 1,000 by adding a "bar" or "overline", thus:

• Template:Rn = 4,000
• Template:Rn = 25,000

The vinculum came into use in the late Republic, and it was a common alternative to the apostrophic ↀ during the Imperial era around the Roman world (M for '1000' was not in use until the Medieval period). It continued in use in the Middle Ages, though it became known more commonly as , and it appears in modern editions of classical and medieval Latin texts.

In an extension of the , a three-sided box (now sometimes printed as two vertical lines and a ) is used to multiply by 100,000, thus:

• Template:RnTemplate:NbspTemplate:Rn p. = 1,332,000 paces (1,332 Roman miles).Template:Efn

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.

Other

• There are some examples of year numbers after 1000 written as two Roman numerals 1–99, e.g. 1613 as Template:Rn, corresponding to the common reading "sixteen thirteen" of such year numbers in English, or 1519 as Template:Rn as in French quinze-cent-dix-neuf (fifteen-hundred and nineteen), and similar readings in other languages.

• In some French texts from the 15th century and later, one finds constructions like Template:Rn for 99, reflecting the French reading of that number as (four-score and nineteen). Similarly, in some English documents one finds, for example, 77 written as "Template:Rn" (which could be read "three-score and seventeen").

• A medieval accounting text from 1301 renders numbers like 13,573 as "Template:Rn", that is, "13×1000 + 5×100 + 3×20 + 13".

Origin

The system is closely associated with the ancient city-state of Rome and the Empire that it created. However, due to the scarcity of surviving examples, the origins of the system are obscure and there are several competing theories, all largely conjectural.

Etruscan numerals

Rome was founded sometime between 850 and 750 BC, next to the southern edge of the Etruscan domain, which covered a large part of north-central Italy.

The Roman numerals, in particular, are directly derived from the Etruscan number symbols: Template:Angbr, Template:Angbr, Template:Angbr, Template:Angbr, and Template:Angbr 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 Template:Angbr and Template:Angbr resembled letters of the Etruscan alphabet, but Template:Angbr, Template:Angbr, and Template:Angbr 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.

Early Roman numerals

The early Roman numerals for 1, 10, and 100 were the Etruscan ones: Template:Angbr, Template:Angbr, and Template:Angbr. The symbols for 5 and 50 changed from Template:Angbr and Template:Angbr to Template:Angbr and Template:Angbr at some point. The latter had flattened to Template:Angbr (an inverted T) by the time of Augustus, and soon afterwards became identified with the graphically similar letter Template:Angbr.

The symbol for 100 was written variously as Template:Angbr or Template:Angbr, and was then abbreviated to Template:Angbr or Template:Angbr, with Template:Angbr (which matched the Latin letter C) finally winning out. It might have helped that C was the initial letter of , Latin for "hundred".

The numbers 500 and 1000 were denoted by Template:Rn or Template:Rn overlaid with a box or circle. Thus, 500 was like a Template:Rn superimposed on a Template:Rn or Template:Rn, making it look like Template:Rn. It became Template:Rn or Template:Rn by the time of Augustus, under the graphic influence of the letter Template:Rn. It was later identified as the letter Template:Rn; an alternative symbol for "thousand" was a Template:Rn, and half of a thousand or "five hundred" is the right half of the symbol, Template:Rn, and this may have been converted into Template:Rn.

The notation for 1000 was a circled or boxed Template:Rn: Ⓧ, Template:Rn, Template:Rn, and by Augustan times was partially identified with the Greek letter Template:Rn phi. Over time, the symbol changed to Template:Rn and Template:Rn. The latter symbol further evolved into Template:Rn, then Template:Rn, and eventually changed to Template:Rn under the influence of the Latin word mille "thousand".

According to Paul Kayser, the basic numerical symbols were Template:Rn, Template:Rn, Template:Rn and Template:Rn (or Template:Rn) and the intermediate ones were derived by taking half of those (half an Template:Rn is Template:Rn, half a Template:Rn is Template:Rn and half a Template:Rn is Template:Rn). Then 𐌟 and ↆ developed as mentioned above.

File:Colosseum-Entrance LII.jpg

Entrance to section Template:Rn (52) of the Colosseum, with numerals still visible

Classical Roman numerals

The Colosseum was constructed in Rome in CE 72–80, and while the original perimeter wall has largely disappeared, the numbered entrances from Template:Rn (23) to Template:Rn (54) survive, to demonstrate that in Imperial times Roman numerals had already assumed their classical form: as largely standardised in current use. The most obvious anomaly (a common one that persisted for centuries) is the inconsistent use of subtractive notation - while Template:Rn is used for 40, Template:Rn is avoided in favour of Template:Rn: in fact, gate 44 is labelled Template:Rn.

Use in the Middle Ages and Renaissance

Lower case, or minuscule, letters were developed in the Middle Ages, well after the demise of the Western Roman Empire, and since that time lower-case versions of Roman numbers have also been commonly used: Template:Rn, Template:Rn, Template:Rn, Template:Rn, and so on.

File:Excerpt from BnF ms. 23112 fr., fol. 343v.png

13th century example of Template:Rn.

Since the Middle Ages, a "Template:Rn" has sometimes been substituted for the final "Template:Rn" of a "lower-case" Roman numeral, such as "Template:Rn" for 3 or "Template:Rn" for 7. This "Template:Rn" can be considered a swash variant of "Template:Rn". Into the early 20th century, the use of a final "Template:Rn" was still sometimes used in medical prescriptions to prevent tampering with or misinterpretation of a number after it was written.

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 "Template:Rn" for "Template:Rn", or "Template:Rn" for "Template:Rn"), while others serve as abbreviations for compound numerals ("Template:Rn" for "Template:Rn", or "Template:Rn" for "Template:Rn"). 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.

Number	Medieval abbreviation	Notes and etymology
5	Template:Rn	Resembles an upside-down V. Also said to equal 500.
6	ↅ	Either from a ligature of Template:Rn, or from digamma (ϛ), the Greek numeral 6 (sometimes conflated with the στ ligature).
7	Template:Rn, Template:Rn	Presumed abbreviation of , Latin for 7.
11	Template:Rn	Presumed abbreviation of , French for 11.
40	Template:Rn	Presumed abbreviation of English forty.
70	Template:Rn	Also could stand for 7, with the same derivation.
80	Template:Rn
90	Template:Rn	Presumed abbreviation of , Latin for 90. (Ambiguous with Template:Rn for "nothing" (nihil)).
150	Template:Rn	Possibly derived from the lowercase y's shape.
151	Template:Rn	Unusual, origin unknown; also said to stand for 250.
160	Template:Rn	Possibly derived from Greek tetra, as 4 × 40 = 160.
200	Template:Rn	Could also stand for 2 (see also 𐆙, the symbol for the dupondius). From a barring of two Template:Rn's.
250	Template:Rn
300	Template:Rn
400	Template:Rn, Template:Rn
500	Template:Rn	Redundant with Template:Rn; abbreviates , Latin for 500. Also sometimes used for 500,000.
800	Template:Rn	Borrowed from Gothic.
900	Template:Rn	Borrowed from Gothic.
2000	Template:Rn
9000	Template:Rn	Cappelli notes that the T with double dot is only attested for Spanish-suited playing cards.

Chronograms, messages with dates encoded into them, were popular during the Renaissance era. The chronogram would be a phrase containing the letters Template:Rn, Template:Rn, Template:Rn, Template:Rn, Template:Rn, Template:Rn, and Template:Rn. By putting these letters together, the reader would obtain a number, usually indicating a particular year.

Modern use

By the 11th century, Arabic numerals had been introduced into Europe from al-Andalus, by way of Arab traders and arithmetic treatises. Roman numerals, however, proved very persistent, remaining in common use in the West well into the 14th and 15th centuries, even in accounting and other business records (where the actual calculations would have been made using an abacus). Replacement by their more convenient "Arabic" equivalents was quite gradual, and Roman numerals are still used today in certain contexts. A few examples of their current use are:

[[File:Carlos IV Coin.jpg|thumb|upright=1.1|Spanish Real using Template:Rn instead of Template:Rn as regnal number of [[Charles IV of Spain|Charles Template:Rn of Spain]].|alt=]]

• Names of monarchs and popes, e.g. Elizabeth II of the United Kingdom, Pope Leo XIV. These are referred to as regnal numbers and are usually read as ordinals; e.g. Template:Rn is pronounced "the second". This tradition began in Europe sporadically in the Middle Ages, gaining widespread use in England during the reign of Henry VIII. Previously, the monarch was not known by numeral but by an epithet such as Edward the Confessor. Some monarchs (e.g. Charles IV of Spain, Louis XIV of France and William IV of Great Britain) seem to have preferred the use of Template:Rn instead of Template:Rn on their coinage (see illustration).
• Generational suffixes, particularly in the U.S., for people sharing the same name across generations, such as William Howard Taft IV. These are also usually read as ordinals.
• In the French Republican Calendar, initiated during the French Revolution, years were numbered by Roman numerals – from the year Template:Rn (1792) when this calendar was introduced to the year Template:Rn (1805) when it was abandoned.

• File:Cambridge Main Public Library 1888.jpg

  The year of construction of the Cambridge Public Library (Massachusetts, U.S.), 1888, displayed in "standard" Roman numerals on its facade.

  The year of production of films, television shows and other works of art within the work itself. Outside reference to the work will use regular Arabic numerals.
• Hour marks on timepieces. In this context, 4 is often written Template:Rn.
• The year of construction on building façades and cornerstones.
• Page numbering of prefaces and introductions of books, and sometimes of appendices and annexes, too.
• Book volume and chapter numbers, as well as the several acts within a play (e.g. Act Template:Rn, Scene 2).
• Sequels to some films, video games, and other works (as in Rocky II, Grand Theft Auto V, Myst III: Exile).
• Outlines that use numbers to show hierarchical relationships.
• Occurrences of a recurring grand event, for instance:
  • The Summer and Winter Olympic Games (e.g. the XXI Olympic Winter Games; the Games of the XXX Olympiad).
  • The Super Bowl, the annual championship game of the National Football League (e.g. Super Bowl XLII; Super Bowl 50 was a one-time exception).
  • WrestleMania, the annual professional wrestling event for WWE (e.g. WrestleMania XXX). This usage has also been inconsistent.

Specific disciplines

In astronautics, United States rocket model variants are sometimes designated by Roman numerals, e.g. Titan I, Titan II, Titan III, Saturn I, Saturn V.

In astronomy, the natural satellites or "moons" of the planets are designated by capital Roman numerals appended to the planet's name. For example, Titan's designation is Saturn Template:Rn.

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 cations which can take on several different positive charges. They are also used for naming phases of polymorphic crystals, 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 Template:Rn" is sometimes seen for "grade 9".

File:9th Aero Squadron AEF.jpg

Stylised "Template:Rn" represents "9" in unit emblem of 9th Aero Squadron AEF, 1918.

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 numbering UK Acts of Parliament within a given year (a given session until 1963), local acts have lowercase Roman numerals, whereas public acts have plain Arabic numerals and personal acts have italic Arabic numerals.

In mathematics (including trigonometry, statistics, and calculus), when a graph includes negative numbers, its quadrants are named using Template:Rn, Template:Rn, Template:Rn, and Template:Rn. 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:

• Movements are often numbered using Roman numerals.
• In Roman numeral analysis, harmonic function is identified using Roman numerals.
• Individual strings of stringed instruments, such as the violin, are often denoted by Roman numerals, with higher numbers denoting lower strings.

In pharmacy, Roman numerals were used with the now largely obsolete apothecaries' system of measurement: including Template:Rn to denote "one half" and Template:Rn 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.

File:Eire Frankng I-IV-1986.jpg

Example of postage stamp from Ireland (Éire) franked using Roman numeral for the month

In sport the team containing the "top" players and representing a nation or province, a club or a school at the highest level in (say) rugby union is often called the "1st Template:Rn", while a lower-ranking cricket or American football team might be the "3rd Template:Rn".

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 Template:Rn, as this translation of the Old Testament into Greek is named for the legendary number of its translators (septuaginta being Latin for "seventy").

Modern use in European languages other than English

Some uses that are rare or never seen in English-speaking countries may be relatively common in parts of continental Europe and in other regions (e.g. Latin America) that use a European language other than English. For instance:

Capital or small capital Roman numerals are widely used in Romance languages to denote centuries, e.g. the French and the Spanish (not ) for "18th century". Some Slavic and Turkic languages (especially in and adjacent to Russia) similarly favour Roman numerals (e.g. Russian , Azeri or Polish ). On the other hand, in Turkish and some Central European Slavic languages, like most Germanic languages, one writes "18." (with a period) before the local word for "century" (e.g. Turkish , Czech ).

When typing on Russian typewriters, the Roman-numeral "V" was replaced with "У" because the letter "V" was absent in the Russian Cyrillic alphabet. Additionally, the Roman-numeral "I" was replaced with "1", since this letter had been removed from the Russian alphabet by the 1918 reform of orthography. For example, XVIII was typed as ХУ111. This style is sometimes maintained even when typing on a computer, either out of habit or due to the inconvenience of switching between Latin and Russian script for one or two letters.

File:Yeltsin-authograph-1988.gif

Boris Yeltsin's signature, dated 10 November 1988, rendered as 10.Template:Rn.'88.

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 month is written in Roman numerals, while the day is in Arabic numerals: "4.Template:Rn.1789" and "Template:Rn.4.1789" both refer unambiguously to 4 June 1789.

File:DarboLaikas.jpg

Business hours table on a shop window in Vilnius, Lithuania.

Roman numerals are sometimes used to represent the days of the week 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 Template:Rn. Sunday is represented by Template:Rn. 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 closed on Sundays. Note that the listing uses 24-hour time.

File:Roma - strada statale 4 - segnale di progressiva ettometrica 17+900.jpg

Sign at 17.9 km on route SS4 Salaria, north of Rome, Italy.

Roman numerals may also be used for floor numbering. For instance, apartments in central Amsterdam are indicated as 138-Template:Rn, 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 .

In Italy, where roads outside built-up areas have kilometre signs, major roads and motorways also mark 100-metre subdivisionals, using Roman numerals from Template:Rn to Template:Rn for the smaller intervals. The sign Template:Sfrac 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 Italian 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.

Unicode

The "Number Forms" block of the Unicode computer character set standard has a number of Roman numeral symbols in the range of code points from U+2160 to U+2188. This range includes both upper- and lowercase numerals, as well as pre-combined characters for numbers up to 12. One justification for the existence of pre-combined numbers is to facilitate the setting of multiple-letter numbers (such as VIII) on a single horizontal line in Asian vertical text. The Unicode standard, however, includes special Roman numeral code points for compatibility only, stating that "[f]or most purposes, it is preferable to compose the Roman numerals from sequences of the appropriate Latin letters". The block also includes some symbols for large numbers, an old variant of "Template:Rn" (50) similar to the Etruscan character, the Claudian letter "reversed C", etc.

Further reading

• Aczel, Amir D. 2015. Finding Zero: A Mathematician's Odyssey to Uncover the Origins of Numbers. 1st edition. New York: Palgrave Macmillan.
• Goines, David Lance. A Constructed Roman Alphabet: A Geometric Analysis of the Greek and Roman Capitals and of the Arabic Numerals. Boston: D.R. Godine, 1982.
• Houston, Stephen D. 2012. The Shape of Script: How and Why Writing Systems Change. Santa Fe, NM: School for Advanced Research Press.
• Taisbak, Christian M. 1965. "Roman numerals and the abacus." Classica et medievalia 26: 147–60.