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: using instead of as regnal number of
Charles 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. 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 instead of 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 (1792) when this calendar was introduced to the year (1805) when it was abandoned. • (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 . • 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 , 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 . 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 " is sometimes seen for "grade 9". 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 citing
UK Acts of Parliament within a given year (a given
session until 1963), the chapter of a
local act is given in lowercase Roman numerals, whereas that of a
public act has plain Arabic numerals and a
personal act has
italic Arabic numerals. 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: •
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 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
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 ", 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 ( 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 , 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. 's signature, dated 10 November 1988, rendered as 10..'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 is written in Roman numerals, while the day is in Arabic numerals: "4..1789" and ".4.1789" both refer unambiguously to 4 June 1789. , Lithuania. 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
closed on Sundays. Note that the listing uses 24-hour time. , north of Rome, Italy. 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 . In Italy, where roads outside built-up areas have
kilometre signs, 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
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==