Solidus (coin)

The solidus (Latin for "solid"; pl. solidi), nomisma (Greek: νόμισμα, nómisma, lit. "coin"), or bezant was originally a relatively pure gold coin issued in the Late Roman Empire. Under Constantine, who introduced it on a wide scale, it had a weight of about 4.5 grams. It was largely replaced in Western Europe by Pepin the Short's currency reform, which introduced the silver-based pound/shilling/penny system, under which the shilling (Latin: solidus) functioned as a unit of account equivalent to 12 pence, eventually developing into the French sou. In Eastern Europe, the nomisma was gradually debased by the Byzantine emperors until it was abolished by Alexius I in 1092, who replaced it with the hyperpyron, which also came to be known as a "bezant". The Byzantine solidus also inspired the originally slightly less pure Arab dinar.

In late Antiquity and the Middle Ages, the solidus also functioned as a unit of weight equal to 1/72 of a pound.

Solidus of Constantine I, minted in AD 324 or 325

Roman coinage

The solidus was introduced by Diocletian in AD 301 as a replacement of the aureus, composed of relatively solid gold and minted 60 to the Roman pound. His minting was on a small scale, however, and the coin only entered widespread circulation under Constantine I after AD 312, when it permanently replaced the aureus.[1] Constantine's solidus was struck at a rate of 72 to a Roman pound (of about 326.6 g) of pure gold; each coin weighed 24 Greco-Roman carats (189 mg each),[2] or about 4.5 grams of gold per coin. By this time, the solidus was worth 275,000 increasingly debased denarii. With the exception of the early issues of Constantine the Great and the odd usurpers the solidus today is a much more affordable gold Roman coin to collect compared to the older aureus. Especially those of Valens Honorius and later Byzantine issues. The solidus was maintained essentially unaltered in weight, dimensions and purity until the 10th century. During the 6th and 7th centuries "lightweight" solidi of 20, 22 or 23 siliquae (one siliqua was 1/24 of a solidus) were struck along with the standard weight issues, presumably for trade purposes or to pay tribute. Many of these lightweight coins have been found in Europe, Russia and Georgia. The lightweight solidi were distinguished by different markings on the coin, usually in the exergue for the 20 and 22 siliquae coins and by stars in the field for the 23 siliquae coins.

Solidus Julian-transparent
Solidus of Julian, c. 361.

In theory the solidus was struck from pure gold, but because of the limits of refining techniques, in practice the coins were often about 23k fine (95.8% gold). In the Greek-speaking world during the Roman period, and then in the Byzantine economy, the solidus was known as the νόμισμα nomisma (plural nomismata).[2] In the 10th century Emperor Nicephorus II Phocas (963–969) introduced a new lightweight gold coin called the tetarteron nomisma that circulated alongside the solidus, and from that time the solidus (nomisma) became known as the ἱστάμενον νόμισμα histamenon nomisma in the Greek speaking world. Initially it was difficult to distinguish the two coins, as they had the same design, dimensions and purity, and there were no marks of value to distinguish the denominations. The only difference was the weight. The tetarteron nomisma was a lighter coin, about 4.05 grams, but the histamenon nomisma maintained the traditional weight of 4.5 grams. To eliminate confusion between the two, from the reign of Basil II (975–1025) the solidus (histamenon nomisma) was struck as a thinner coin with a larger diameter, but with the same weight and purity as before. From the middle of the 11th century the larger diameter histamenon nomisma was struck on a concave flan, though the smaller tetarteron nomisma continued to be struck on a smaller flat flan.

Tremissis Avitus-RIC 2402
Avitus tremissis, one-third of a solidus, c.AD 456.

Former money changer Michael IV the Paphlagonian (1034–41) assumed the throne of Byzantium in 1034 and began the slow process of debasing both the tetarteron nomisma and the histamenon nomisma. The debasement was gradual at first, but then accelerated rapidly: about 21 carats (87.5% pure) during the reign of Constantine IX (1042–1055), 18 carats (75%) under Constantine X (1059–1067), 16 carats (66.7%) under Romanus IV (1068–1071), 14 carats (58%) under Michael VII (1071–1078), 8 carats (33%) under Nicephorus III (1078–1081) and 0 to 8 carats during the first eleven years of the reign of Alexius I (1081–1118). Alexius reformed the coinage in 1092 and eliminated the solidus (histamenon nomisma) altogether. In its place he introduced a new gold coin called the hyperpyron nomisma at about 20.5k fine (85%). The weight, dimensions and purity of the hyperpyron nomisma remained stable until the fall of Constantinople to the Crusaders in 1204. After that time the exiled Empire of Nicea continued to strike a debased hyperpyron nomisma. Michael VIII recaptured Constantinople in 1261, and the Byzantine Empire continued to strike the debased hyperpyron nomisma until the joint reign of John V and John VI (1347–1354). After that time the hyperpyron nomisma continued as a unit of account, but it was no longer struck in gold.

From the 4th to the 11th centuries, solidi were minted mostly at the Constantinopolitan Mint, but also in Thessalonica, Trier, Rome, Milan, Ravenna, Syracuse, Alexandria, Carthage, Jerusalem and other cities. During the 8th and 9th centuries the Syracuse mint produced a large number of solidi that failed to meet the specifications of the coins produced by the imperial mint in Constantinople. The Syracuse solidi were generally lighter (about 3.8g) and only 19k fine (79% pure).

Although imperial law forbade merchants from exporting solidi outside imperial territory, many solidi have been found in Russia, Central Europe, Georgia, and Syria. In the 7th century they became a desirable circulating currency in Arabian countries. Since the solidi circulating outside the empire were not used to pay taxes to the emperor, they did not get reminted, and the soft pure-gold coins quickly became worn.[2]

Through the end of the 7th century, Arabian copies of solidi – dinars minted by the caliph Abd al-Malik ibn Marwan, who had access to supplies of gold from the upper Nile – began to circulate in areas outside the Byzantine Empire. These corresponded in weight to only 20 carats (4.0 g), but matched the weight of the lightweight (20 siliquae) solidi that were circulating in those areas. The two coins circulated together in these areas for a time.[2]

The solidus was not marked with any face value throughout its seven-century manufacture and circulation. Fractions of the solidus known as semissis (half-solidi) and tremissis (one-third solidi) were also produced.

The word soldier is ultimately derived from solidus, referring to the solidi with which soldiers were paid.[3]

Impact on world currencies

In medieval Europe, where the only coin in circulation was the silver penny (denier), the solidus was used as a unit of account equal to 12 deniers. Variations on the word solidus in the local language gave rise to a number of currency units:


Northern Gaul sou 440 450 4240mg
Northern Gaul "sou", 440–450, 4240mg.

In the French language, which evolved directly from common or vulgar Latin over the centuries, solidus changed to soldus, then solt, then sol and finally sou. No gold solidi were minted after the Carolingians adopted the silver standard; thenceforward the solidus or sol was a paper accounting unit equivalent to one-twentieth of a pound (librum or livre) of silver and divided into 12 denarii or deniers.[4] The monetary unit disappeared with decimalisation and introduction of the franc during the French revolution (1st republic) in 1795, but the coin of 5 centimes, the twentieth part of the franc, inherited the name "sou" as a nickname: in the first half of the 20th century, a coin or an amount of 5 francs was still often referred to as cent sous.

To this day, in French around the world, solde means the balance of an account or invoice, and is the specific name of a soldier's salary. Although the sou as a coin disappeared more than two centuries ago, the word is still used as a synonym of money in many French phrases: avoir des sous is being rich, être sans un sou is being poor (same construction as "penniless").


In Canadian French, sou and sou noir are commonly employed terms for the Canadian cent. Cenne and cenne noire are also regularly used. The European French centime is not used in Quebec. In Canada one hundredth of a dollar is officially known as a cent (pronounced /sɛnt/) in both English and French. However, in practice, a feminine form of cent, cenne (pronounced /sɛn/) has mostly replaced the official "cent" outside bilingual areas. Spoken use of the official masculine form of cent is uncommon in francophone-only areas of Canada. Quarter dollar coins in colloquial Quebec French are sometimes called trente-sous (thirty cents), because of a series of changes in terminology, currencies, and exchange rates. After the British conquest of Canada in 1759, French coins gradually fell out of use, and sou became a nickname for the halfpenny, which was similar in value to the French sou. Spanish pesos and U.S. dollars were also in use, and from 1841 to 1858 the exchange rate was fixed at $4 = £1 (or 400¢ = 240d). This made 25¢ equal to 15d, or 30 halfpence i.e. trente sous. In 1858, pounds, shillings, and pence were abolished in favour of dollars and cents, and the nickname sou began to be used for the 1¢ coin, but the term un trente-sous for a 25¢ coin has endured.[5] In the vernacular Quebec French sous and cennes are also frequently used to refer to money in general, especially small amounts.


The name of the medieval Italian silver soldo (plural soldi), coined since the 11th century, was derived from solidus.

This word is still in common use today in Italy in its plural soldi with the same meaning as the English equivalent "money". The word "saldo", like the French solde mentioned above, means the balance of an account or invoice. It also means "seasonal rebate", probably by contamination between the original meaning and the English word "sales".

Spain and Peru, Portugal and Brazil

As with soldier in English, the Spanish and Portuguese equivalent is soldado (almost the same pronunciation). The name of the medieval Spanish sueldo and Portuguese soldo (which also means salary) were derived from solidus; the Filipino term sweldo is derived from the Spanish.

The Spanish and Portuguese word saldo, like the French solde, means the balance of an account or invoice. It is also used in some other languages, such as German and Afrikaans.

Some have suggested that the Peruvian unit of currency, the sol, is derived from solidus, but the standard unit of Peruvian currency was the real until 1863. Throughout the Spanish world the dollar equivalent was 8 reales ("pieces of eight"), which circulated legally in the United States until 1857. We hear echoes of that time in the expression "two bits" for a quarter dollar, and the real was last used for accounting in the US stock market, which traded in 1/8 dollars until 2001.

The Peruvian sol was introduced at a rate of 5.25 per British Pound, or just under four shillings (the legacy soldus). The term soles de oro was introduced in 1933, three years after Peru had actually abandoned the gold standard. In 1985 the Peruvian sol was replaced at one thousand to one by the inti, representing the sun god of the Incas. By 1991 it had to be replaced with a new sol at a million to one, after which it remained reasonably stable.

United Kingdom

King Offa of Mercia began minting silver pennies on the Carolingian system c. 785. As on the continent, English coinage was restricted for centuries to the penny, while the scilling, understood to be the value of a cow in Kent or a sheep elsewhere,[6] was merely a unit of account equivalent to 12 pence. The Tudors minted the first shilling coins. Prior to decimalization in the United Kingdom in 1971, the abbreviation s. (from solidus) was used to represent shillings, just as d. (denarius) and £ (libra) were used to represent pence and pounds respectively.

Under the influence of the old long Sſ⟩, the abbreviations "£sd" eventually developed into the use of a slash/⟩, which gave rise to that symbol's ISO and Unicode name "solidus".

See also



  1. ^ "Reproduction Solidus". Dorchesters. Retrieved 10 July 2015.
  2. ^ a b c d Porteous 1969
  3. ^ "Merriam-Webster Online Dictionary". Merriam-Webster. Retrieved 2008-12-05.
  4. ^ Spufford, Peter (1993). Money and its use in medieval Europe. Cambridge University Press. pp. 7–9, 18–19, 25, 33–35, 37, 50–52, 397, 400. ISBN 978-0-521-37590-0.
  5. ^ Frédéric Farid (26 September 2008). "Pourquoi trente sous = 25 cents ?". Retrieved 6 October 2010.
  6. ^ Hodgkin, Thomas (1906). The history of England … to the Norman conquest. London, New York and Bombay: Longmans, Green, and Co. p. 234.


  • Porteous, John (1969). "The Imperial Foundations". Coins in history : a survey of coinage from the reform of Diocletian to the Latin Monetary Union. Weidenfeld and Nicolson. pp. 14–33. ISBN 0-297-17854-7.

External links


The argenteus was a silver coin produced by the Roman Empire from the time of Diocletian's coinage reform in AD 294 to ca. AD 310. It was of similar weight and fineness as the denarius of the time of Nero. The coin was produced at a theoretical weight of 1/96th of a Roman pound (about 3 grams), as indicated by the Roman numeral XCVI on the coin's reverse.

Argenteus, meaning "of silver" in Latin, was first used in Pliny's Natural History in the phrase "argenteus nummus" (silver coin). The 4th-century historian Ammianus uses the same phrase, however there is no indication that this is the official name for a denomination. The Historia Augusta uses the phrase to refer to several fictitious coins.

Byzantine silk

Byzantine silk is silk woven in the Byzantine Empire (Byzantium) from about the fourth century until the Fall of Constantinople in 1453.

The Byzantine capital of Constantinople was the first significant silk-weaving center in Europe. Silk was one of the most important commodities in the Byzantine economy, used by the state both as a means of payment and of diplomacy.Raw silk was bought from China and made up into fine fabrics that commanded high prices throughout the world. Later, silkworms were smuggled into the Empire and the overland silk trade gradually became less important. After the reign of Justinian I, the manufacture and sale of silk became an imperial monopoly, only processed in imperial factories, and sold to authorized buyers.Byzantine silks are significant for their brilliant colours, use of gold thread, and intricate designs that approach the pictorial complexity of embroidery in loom-woven fabric. Byzantium dominated silk production in Europe throughout the Early Middle Ages, until the establishment of the Italian silk-weaving industry in the 12th century and the conquest and break-up of the Byzantine Empire in the Fourth Crusade (1204).

Constans II

Constans II (Greek: Κώνστας Β', Kōnstas II; Latin: Heraclius Constantinus Augustus or Flavius Constantinus Augustus; 7 November 630 – 15 September 668), also called Constantine the Bearded (Κωνσταντῖνος ὁ Πωγωνάτος Kōnstantinos ho Pogonatos), was emperor of the Byzantine Empire from 641 to 668. He was the last emperor to serve as consul, in 642. Constans is a nickname given to the Emperor, who had been baptized Herakleios and reigned officially as Constantine. The nickname established itself in Byzantine texts and has become standard in modern historiography.


The denarius (/deː.ˈnaː.rɪ.ʊs/, pl. dēnāriī, /deː.ˈnaː.rɪ.iː/) was the standard Roman silver coin from its introduction in the Second Punic War c. 211 BC to the reign of Gordian III (AD 238–244), when it was gradually replaced by the Antoninianus. It continued to be minted in very small quantities, likely for ceremonial purposes, until and through the tetrarchy (293–313).The word dēnārius is derived from the Latin dēnī "containing ten", as its value was originally of 10 assēs. The word for "money" descends from it in Italian (denaro), Slovene (denar), Portuguese (dinheiro), and Spanish (dinero). Its name also survives in the dinar currency.

Its symbol is represented in Unicode as 𐆖 (U+10196), however it can also be represented as X̶ (capital letter X with combining long stroke overlay).

Edict on Maximum Prices

The Edict on Maximum Prices (Latin: Edictum de Pretiis Rerum Venalium, "Edict Concerning the Sale Price of Goods"; also known as the Edict on Prices or the Edict of Diocletian) was issued in 301 by Roman Emperor Diocletian.

The Edict was probably issued from Antioch or Alexandria and was set up in inscriptions in Greek and Latin. It now exists only in fragments found mainly in the eastern part of the empire, where Diocletian ruled. However, the reconstructed fragments have been sufficient to estimate many prices for goods and services for historical economists (although, it should be stressed, the Edict attempts to set maximum prices, not fixed ones).

The Edict on Maximum Prices is still the longest surviving piece of legislation from the period of the Tetrarchy. The Edict was criticized by Lactantius, a rhetorician from Nicomedia, who blamed the emperors for the inflation and told of fighting and bloodshed that erupted from price tampering.

By the end of Diocletian's reign in 305, the Edict was for all practical purposes ignored. The Roman economy as a whole was not substantively stabilized until Constantine's coinage reforms in the 310s.

Forsbrook Pendant

The Forsbrook Pendant is a piece of Anglo Saxon jewellery found in Forsbrook, Staffordshire, England and sold to the British Museum in 1879. It is a 7th-century setting of a 4th-century gold Roman coin in gold cellwork with garnet and blue glass inlays.

French sol

The sol, later called a sou, is the name of a number of different coins, for accounting or payment, dating from Antiquity to today. The name is derived from the solidus. Its longevity of use anchored it in many expressions of the French language.

Roman currency

Roman currency for most of Roman history consisted of gold, silver, bronze, orichalcum and copper coinage (see: Roman metallurgy). From its introduction to the Republic, during the third century BC, well into Imperial times, Roman currency saw many changes in form, denomination, and composition. A persistent feature was the inflationary debasement and replacement of coins over the centuries. Notable examples of this followed the reforms of Diocletian. This trend continued into Byzantine times.

Because of the economic power and longevity of the Roman state, Roman currency was widely used throughout western Eurasia and northern Africa from classical times into the Middle Ages. It served as a model for the currencies of the Muslim caliphates and the European states during the Middle Ages and the Modern Era. Roman currency names survive today in many countries (e.g., the Arabic dinar (from the denarius coin), the Peruvian sol (from the solidus coin),the British pound and Mexican peso (both translations of the Roman libra)).


The siliqua (plural siliquae) is the modern name given (without any ancient evidence to confirm the designation) to small, thin, Roman silver coins produced in the 4th century A.D. and later. When the coins were in circulation, the Latin word siliqua was a unit of weight defined by one late Roman writer as one twenty-fourth of the weight of a Roman solidus.

"Siliqua vicesima quarta pars solidi est, ab arbore, cuius semen est, vocabulum tenens."A siliqua is one-twentyfourth of a solidus [coin] and the name is taken from the seed of a tree.

The term siliqua comes from the siliqua graeca, the seed of the carob tree, which in the Roman weight system is equivalent to 1/6 of a scruple (1/1728 of a Roman pound or about 0.19 grams).

The term has been applied in modern times to various silver coins on the premise that the coins were valued at 1/24 of the gold solidus (which weighed 1/72 of a Roman pound) and therefore represented a siliqua of gold in value. Since gold was worth about 14 times as much as silver in ancient Rome, such a silver coin would have a theoretical weight of 2.7 grams. There is little historical evidence to support this premise. This has not prevented the term from being applied today to silver coins issued by Constantine, which initially weighed 3.4 grams, or the later silver coin of Constantius II, which weighed about 2.2 grams and 18 mm, and is sometimes called a "light" or "reduced" siliqua to differentiate it. The term is one of convenience, as no name for these coins is indicated by contemporary sources. Thin silver coins as late as the 7th century which weigh about 2 to 3 grams are known as siliquae by numismatic convention.

The majority of examples suffer striking cracks (testimony to their fast production) or extensive clipping (removing silver from the edge of the coin), and thus to find both an untouched and undamaged example is fairly uncommon. It is thought that by clipping, siliquae provided the first coinage of the Saxons, as this reduced them to around the same size as a sceat, and there is considerable evidence from archaeological sites of this period, that siliquae and many other Roman coins were utilised by Saxons as pendants, lucky charms, currency and curiosities.


Solidus (Latin for "solid") may refer to:

Solidus (coin), a Roman coin of nearly solid gold

Solidus (punctuation), an historical name of the slash ( / ), from its former use marking the English shilling

Solidus (chemistry), the line on a phase diagram below which a substance is completely solid

Solidus Snake, a character in Metal Gear Solid 2: Sons of Liberty

Theophylact (son of Michael I)

Theophylact or Theophylaktos (Greek: Θεοφύλακτος; c. 793 – 15 January 849) was the eldest son of the Byzantine emperor Michael I Rhangabe (r. 811–813) and grandson, on his mother's side, of Nikephoros I (r. 802–811). He was junior co-emperor alongside his father for the duration of the latter's reign, and was tonsured, castrated, and exiled to Plate Island after his overthrow, under the monastic name Eustratius.

Republican era
Early Empire
Diocletian era
Late Empire
First period
(498 – ca. 700)
Second period
(ca. 700 – 1092)
Third period
(1092 – ca. 1300)
Fourth period
(ca. 1300 – 1350s)
Fifth period
(1367 – 1453)
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