The
ancient Roman units of measurement were built on the
Hellenic systemAncient Greek units of measurement would later create the foundation of Egyptian, and formed the basis of the later Roman system.Generally speaking, standards of measurement within the ancient Greek world varied according to location and epoch. Systems of ancient weights and measures evolved as...
with
Egyptian-Length:Units of length date back to at least the early dynastic period. In the Palermo stone for instance the level of the Nile river is recorded. During the reign of Pharaoh Djer the height of the river Nile was given as measuring 6 cubits and 1 palm...
,
HebrewBiblical and Talmudic units of measurement, such as the Omer, used primarily by ancient Israelites, appear frequently within the Hebrew Bible as well as in later Judaic scripture, such as the Mishnah and Talmud...
, and
MesopotamianAncient Mesopotamian units of measurement originated in the loosely organized city-states of Early Dynastic Sumer. The units themselves grew out of the tradition of counting tokens used by the Neolithic cultural complex of the Near East. The counting tokens were used to keep accounts of personal...
influences. The
RomanAncient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
units were comparatively consistent and well documented.
Length
| Roman unit |
Latin name |
Feet |
Equivalence |
| one digit |
digitus |
|
18.5 mm |
one inchAn inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...
|
uncia An ' is an ancient Roman unit of length that roughly corresponds to an inch. One uncia is 0.97 inches or 24.6 millimeters. There are twelve in one pes....
|
|
24.6 mm |
| one palm |
palmus |
|
74 mm |
| one foot |
pes |
1 |
29.6 cm |
| one cubit The cubit is a traditional unit of length, based on the length of the forearm. Cubits of various lengths were employed in many parts of the world in Antiquity, in the Middle Ages and into Early Modern Times....
|
cubitus |
|
44.4 cm |
| one step |
gradus |
|
0.74 m |
| one pace |
passus |
5 |
1.48 m |
| one fathom |
ulna |
6 |
1.78 m |
| one perch |
pertica |
10 |
2.96 m |
| one arpent An arpent is a unit of length and a unit of area. It is a pre-metric French unit based on the Roman actus. It is used in Quebec as well as in some areas of the United States that were part of French Louisiana.-Unit of length:...
|
actus |
120 |
35.5 m |
| one furlong A furlong is a measure of distance in imperial units and U.S. customary units equal to one-eighth of a mile, equivalent to 220 yards, 660 feet, 40 rods, or 10 chains. The exact value of the furlong varies slightly among English-speaking countries....
|
stadium |
625 |
185 m |
one mileA mile is a unit of length, most commonly 5,280 feet . The mile of 5,280 feet is sometimes called the statute mile or land mile to distinguish it from the nautical mile...
|
mille passuum (milliarium) |
5000 |
1.48 km |
| one league A league is a unit of length . It was long common in Europe and Latin America, but it is no longer an official unit in any nation. The league originally referred to the distance a person or a horse could walk in an hour...
|
leuga |
7500 |
2.2225 km |
Notes
- From late Antiquity
Late Antiquity is a periodization used by historians to describe the time of transition from Classical Antiquity to the Middle Ages, in both mainland Europe and the Mediterranean world. Precise boundaries for the period are a matter of debate, but noted historian of the period Peter Brown proposed...
the Roman foot was sometimes divided into unciaeAn ' is an ancient Roman unit of length that roughly corresponds to an inch. One uncia is 0.97 inches or 24.6 millimeters. There are twelve in one pes....
comprising 12 equal parts.
The ancient digit measure, however, largely dominated before the beginning of the Middle AgesThe Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...
.
- A Roman foot was approximately equal to the height of a modern A4 sheet of paper
ISO 216 specifies international standard paper sizes used in most countries in the world today. It defines the "A" and "B" series of paper sizes, including A4, the most commonly available size...
.
Area
| Roman unit |
Latin name |
Acres |
Equivalence |
| one square foot |
pes quadratus |
|
~ 876 cm² |
| one square perch |
scripulum |
|
~ 8.76 m² |
| one aune of furrows |
actus minimus |
|
~ 42 m² |
| one rood |
clima |
|
~ 315 m² |
| one acre |
actus quadratus
also known as acnua |
1 |
~ 1260 m² |
| one yoke |
iugerum |
2 |
~ 2520 m² |
| one morn |
heredium |
4 |
~ 5040 m² |
| one centurie |
centuria |
400 |
~ 50.5 ha The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...
|
| one "quadruplex" |
saltus |
1600 |
~ 201.9 ha |
The Roman acre is the squared Roman arpent, 120 pedes by 120 pedes. This equals 14 400 square feet or about 0.126 hectares.
The Romans also had a unit of area called a
quinariaA quinaria is a Roman unit of area, roughly equal to 4.2 square centimeters . Its primary use was to measure the cross-sectional area of pipes in Roman water distribution systems...
, which was used to measure the cross-sectional area of pipes. One quinaria was considered to be roughly 4.2 cm².
Liquid measures
| Roman unit |
Latin name |
Sesters |
Equivalence |
| one spoonful |
ligula |
|
~ 11.25 ml |
| one dose |
cyathus |
|
~ 45 ml |
| one sixth-sester |
sextans |
|
~ 90 ml |
| one third-sester |
triens |
|
~ 180 ml |
| one half-sester |
hemina |
|
~ 270 ml |
| one double third-sester |
choenix |
|
~ 360 ml |
| one sester |
sextarius |
1 |
~ 540 ml |
| one congius In Ancient Roman measurement, congius was a liquid measure, which contained six sextarii, or the eighth-part of the amphora; that is about 3.25 litres...
|
congius |
6 |
~ 3.25 l |
| one urn |
urna |
24 |
~ 13 l |
| one jar |
amphora |
48 |
~ 26 l |
| one hose |
culleus |
960 |
~ 520 l |
The Roman jar, so-called "amphora quadrantal" is the cubic foot. The congius is half-a-foot cubed. The Roman sester is the sixth of a congius.
Dry measures
| Roman unit |
Latin name |
Pecks |
Equivalence |
| one drawing-spoon |
acetabulum |
|
~ 67.5 ml |
| one quarter-sester |
quartarius |
|
~ 135 ml |
| one half-sester |
hemina |
|
~ 270 ml |
| one sester |
sextarius |
|
~ 540 ml |
| one gallon |
semodius |
|
~ l |
| one peck |
modius |
1 |
~ l |
| one bushel |
quadrantal |
3 |
~ 26 l |
Like the jar, the Roman bushel or "quadrantal" is one cubic foot. It is almost 26.027 litres. One-third of a quandrantal is a Roman peck.
Mass
The units of weight (mass) were mostly based on factors of 12. Several of the unit names were also the names of coins during the
Roman RepublicThe Roman Republic was the period of the ancient Roman civilization where the government operated as a republic. It began with the overthrow of the Roman monarchy, traditionally dated around 508 BC, and its replacement by a government headed by two consuls, elected annually by the citizens and...
and had the same fractional value of a larger base unit: libra for mass and as for coin. The modern mass of the libra is estimated to range from 322 to 327 g (11.4 to 11.5 ).
| Unit of mass | Conversion |
| Centum podium |
1,200 100 libra |
| Mina The mina is an ancient Near Eastern unit of weight equivalent to 60 shekels. The mina, like the shekel, was also a unit of currency; in ancient Greece it was equal to 100 drachmae. In the first century AD, it amounted to about a fourth of the wages earned annually by an agricultural worker...
|
20 uncia |
| Libra (podium) |
12 uncia |
| Deunx |
11 uncia |
| Dextans |
10 uncia |
| Dodrans The dodrans was an Ancient Roman bronze coin produced during the Roman Republic.The dodrans, valued at three-fourth of an as , was produced only twice:...
|
9 uncia |
| Bes The bes was an Ancient Roman bronze coin produced during the Roman Republic. The bes, valued at two-thirds of an as , was only produced in 126 BC by C. Cassius in combination with the dodrans, another very rare denomination which was valued at three-fourths of an as....
|
8 uncia |
| Septunx |
7 uncia |
| Semis The semis was small Roman bronze coin that was valued at half an as. During the Roman Republic, the semis was distinguished by an 'S' or 6 dots...
|
6 uncia |
| Quincunx |
5 uncia |
| Triens The triens was an Ancient Roman bronze coin produced during the Roman Republic valued at one-third of an as . The most common design for the triens was the bust of Minerva and four pellets on the obverse and the prow of a galley on the reverse. It was not a common denomination and was last struck...
|
4 uncia |
| Quadrans The quadrans was a low-value Roman bronze coin worth one quarter of an as. The quadrans was issued from the beginning of cast bronze coins during the Roman Republic with three pellets representing three unciae as a mark of value...
|
3 uncia |
| Sextans The sextans was an Ancient Roman bronze coin produced during the Roman Republic valued at one-sixth of an as . The most common design for the sextans was the bust of Mercury and two pellets on the obverse and the prow of a galley on the reverse...
|
2 uncia |
| Uncia The uncia was a Roman unit of length and of weight .-Republican coin:...
(ounce) |
1 |
| Semuncia A Dock landing ship or Landing ship is a form of amphibious warship designed to support amphibious operations. These amphibious assault ships transport and launch amphibious craft and vehicles with their crews and embarked personnel...
|
uncia |
| Duella A duella was an ancient Roman unit of weight, equivalent to a third of a Roman ounce ....
|
uncia |
| Sicilium |
uncia |
| Miliaresium |
uncia |
SolidusThe solidus was originally a gold coin issued by the Romans, and a weight measure for gold more generally, corresponding to 4.5 grams.-Roman and Byzantine coinage:...
(sextula) |
uncia |
DenariusIn the Roman currency system, the denarius was a small silver coin first minted in 211 BC. It was the most common coin produced for circulation but was slowly debased until its replacement by the antoninianus...
|
uncia |
| Denier |
uncia |
| Scripulum |
denier |
Reference:
Years
The complicated
Roman calendarThe Roman calendar changed its form several times in the time between the founding of Rome and the fall of the Roman Empire. This article generally discusses the early Roman or pre-Julian calendars...
was replaced by the
Julian calendarThe Julian calendar began in 45 BC as a reform of the Roman calendar by Julius Caesar. It was chosen after consultation with the astronomer Sosigenes of Alexandria and was probably designed to approximate the tropical year .The Julian calendar has a regular year of 365 days divided into 12 months...
in 45 BC. In the Julian calendar, an ordinary year is 365 days long, a
leap yearA leap year is a year containing one extra day in order to keep the calendar year synchronized with the astronomical or seasonal year...
is 366 days long. Between 45 BC and 1 AD, leap years occurred at irregular intervals. Starting in the year 4 AD, leap years occurred regularly every four years. Year numbers were rarely used; rather, the year was specified by naming the
Roman consulA consul served in the highest elected political office of the Roman Republic.Each year, two consuls were elected together, to serve for a one-year term. Each consul was given veto power over his colleague and the officials would alternate each month...
s for that year. When a year number was required, the Greek Olympiads were used, or the count of years since the founding of Rome, "
Ab urbe conditaAb urbe condita is Latin for "from the founding of the City ", traditionally set in 753 BC. AUC is a year-numbering system used by some ancient Roman historians to identify particular Roman years...
" in 753 BC. In the
middle agesThe Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...
, the year numbering was changed to the
Anno Domini and Before Christ are designations used to label or number years used with the Julian and Gregorian calendars....
count.
Our currently used
Gregorian calendarThe Gregorian calendar, also known as the Western calendar, or Christian calendar, is the internationally accepted civil calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582, a papal bull known by its opening words Inter...
differs from the Julian calendar in that it skips three leap years every four centuries to more closely approximate the length of the
tropical yearA tropical year , for general purposes, is the length of time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth; for example, the time from vernal equinox to vernal equinox, or from summer solstice to summer solstice...
.
Weeks
The Romans grouped days into an eight-day cycle called a
nundinaIn ancient Roman religion, the dii Novensiles or Novensides are collective deities of obscure significance found in inscriptions, prayer formulary, and both ancient and early-Christian literary texts....
, with every eighth day being a market day.
Independent of the
nundinae,
astrologerAn astrologer practices one or more forms of astrology. Typically an astrologer draws a horoscope for the time of an event, such as a person's birth, and interprets celestial points and their placements at the time of the event to better understand someone, determine the auspiciousness of an...
s kept a seven-day cycle called a
hebdomada where each day corresponded to one of the seven classical planets, with the first day of the week being
Saturn-daySaturday is the day of the week following Friday and preceding Sunday.Saturday is the last day of the week on many calendars and in conventions that consider the week as beginning on Sunday, or the sixth day of the week according to international standard ISO 8601 which was first published in...
, followed by
Sun-daySunday is the day of the week between Saturday and Monday. For most Christians, Sunday is observed as a day for worship of God and rest, due to the belief that it is Lord's Day, the day of Christ's resurrection....
,
Moon-dayMonday is the day of the week between Sunday and Tuesday. According to international standard ISO 8601 it is the first day of the work week. According to the Islamic and Hebrew calendars, Sunday is the first day of the week...
,
Mars-dayTuesday is a day of the week occurring after Monday and before Wednesday.According to international standard ISO 8601, it is the second day of the week, although in some traditions it is the third....
,
Mercury-dayWednesday is a day of the week in the Gregorian calendar. According to international standard ISO 8601, it is the third day of the week. This day is between Tuesday and Thursday...
,
Jove-dayThursday is the fourth day of the week according to the ISO 8601 international standard adopted in most western countries. In countries that use the Sunday-first convention and in the Judeo-Christian calendar it is the fifth day of the week. It falls between Wednesday and Friday...
, and lastly
Venus-dayFriday is the day between Thursday and Saturday. In countries adopting Monday-first conventions as recommended by the international standard ISO 8601, it is the fifth day of the week. It is the sixth day in countries that adopt a Sunday-first convention as in Abrahamic tradition...
. Each astrological day was reckoned to begin at sunrise. The Jews also used a seven-day week, which began Saturday evening. The seventh day of the week they called the
SabbathSabbath in Christianity is a weekly day of rest or religious observance, derived from the Biblical Sabbath.Seventh-day Sabbath observance, i.e. resting from labor from Friday sunset to Saturday sunset, is practiced by seventh-day Sabbatarians...
; the other days they numbered rather than named, except for Friday, which could be called either the Parasceve or the sixth day. Each Jewish day was reckoned to begin at sunset.
ChristianA Christian is a person who adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus of Nazareth as recorded in the Canonical gospels and the letters of the New Testament...
s followed the Jewish seven-day week, except that they commonly called the first day of the week the
Dominica, or the
Lord's dayLord's Day is a Christian name for Sunday, the day of communal worship. It is observed by most Christians as the weekly memorial of the resurrection of Jesus Christ, who is said in the four canonical Gospels of the New Testament to have been witnessed alive from the dead early on the first day of...
. In 321 Constantine the Great gave his subjects every Sunday off in honor of his family's tutelary deity, the
Unconquered SunSol Invictus was the official sun god of the later Roman empire. In 274 Aurelian made it an official cult alongside the traditional Roman cults. Scholars disagree whether the new deity was a refoundation of the ancient Latin cult of Sol, a revival of the cult of Elagabalus or completely new...
, thus cementing the seven-day week into Roman civil society.
Hours
The Romans divided the daytime into twelve
horae or
hourThe hour is a unit of measurement of time. In modern usage, an hour comprises 60 minutes, or 3,600 seconds...
s starting in the morning and ending in the evening. The night was divided into four watches. The duration of these hours varied with seasons; in the winter, when the daylight period was shorter, its 12 hours were correspondingly shorter and its four watches were correspondingly longer.
Astrologers divided the solar day into 24 equal hours, and these astrological hours became the basis for medieval
clockA clock is an instrument used to indicate, keep, and co-ordinate time. The word clock is derived ultimately from the Celtic words clagan and clocca meaning "bell". A silent instrument missing such a mechanism has traditionally been known as a timepiece...
s and our modern 24 hour mean solar day.
Although the division of hours into
minuteA minute is a unit of measurement of time or of angle. The minute is a unit of time equal to 1/60th of an hour or 60 seconds. In the UTC time scale, a minute on rare occasions has 59 or 61 seconds; see leap second. The minute is not an SI unit; however, it is accepted for use with SI units...
s and
secondThe second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
s did not occur until the
middle agesThe Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...
,
ancientClassical antiquity is a broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world...
astrologers had a
minuta equal to a 60th of a day, and a
secunda equal to one 3600th of a day.
External links