Julian solidus, ca. 361.

Avitus tremissis, one-third of a solidus, ca. 456.

The solidus was first introduced by Diocletian around 301, struck at 60 to the Roman pound of pure gold (c. 5.3g) and with an initial value equal to 1000 denarii.^[1] However, Diocletian's solidus was only struck in small quanities, and thus had only minimal economic impact.

The solidus was re-introduced by Constantine I in 312, permanently replacing the aureus as the imperial gold coin of the Roman Empire. The solidus was struck at a rate of 72 from a Roman pound of pure gold, each coin weighing twenty-four Roman/Greek carats^[2], or about 4.5 grams of gold per coin. By this time, the solidus was worth 275,000 increasingly debased denarii.

The solidus maintained essentially unaltered in weight and purity until the 10th century, though in the Greek-speaking world during the Roman period and then in the Byzantine economy it was known as the nomisma (plural nomismata). ^[2] Whenever the coin was taken in by the treasury, it was melted down and reissued. This maintained the evenness of the weight of the circulating solidi, since the coin did not tend to be in circulation for long enough to become worn.^[2]

Minting of the gold coin - unlike the base-metal coins of the time - had no permanently established minting facility. Due to the requirement that taxes were paid in gold, solidus minting operations tended to follow the emperor and his court. For example, solidi were minted in Milan in 353, and in Ravenna after 402. Each of these locations were imperial residences at those times.^[2]

Although merchants were forbidden from using solidi outside of the Byzantine empire, there was sufficient trade in these coins outside of the empire that they became a desirable circulating currency in Arabic countries. Since the solidi circulating outside the empire were not used to pay the taxes to the emperor they did not get re-minted, and the soft pure gold coins quickly became worn.^[2]

Through the end of the 7th century, Arabic copies of solidii - dinars minted by the caliph Abd al-Malik who had access to supplies of gold from the upper Nile - began to circulate in areas outside of the Byzantine empire. These corresponded in weight to only 20 carats, but matched with the weight of the worn solidi that were circulating in those areas at the time. The two coins circulated together in these areas for a time.^[2]

Except in special cases, the solidus was not marked with any face value throughout its seven-century manufacture and circulation. Solidi were wider and thinner than the Aureus, with the exception of some lower quality issues from the Byzantine Empire. 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.

Impact on world currencies

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

France

To this day, sou is used as slang a small coin of little value, as in sans le sou. "I'm broke", "without money". It is also a slang term for the Canadian cent (standard French, cent).

Sou of copper, coined 1767 for Louis XV of France

Italy

The name of the medieval Italian soldo (plural soldi) 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.

Spain and Peru

The name of the medieval Spanish sueldo (which also means salary) was derived from solidus, which is also used in the Philippines as Suweldo. Subsequently the name of the Peruvian sol (more formally sol de oro intended to mean gold solidus) was derived from this name although, because sol actually means sun in Spanish (from the Latin sol), the etymology of the currency's name is commonly misunderstood. To complicate matters, the Sun God was a foremost figure of the Incan Empire that reigned in what is now Peru.

United Kingdom

Until decimalisation in the United Kingdom in 1971, the abbreviation s., from solidus, was used to represent shillings, just as d. and £, from denarius and Libra, were respectively used to represent pence and pounds, leading to the abbreviation "£sd".

References

See also

• Roman currency
• Byzantine coinage
• Solidus (punctuation)
• Slash (punctuation) (also called a solidus)

External links

• Online numismatic exhibit: "This round gold is but the image of the rounder globe" (H.Melville). The charm of gold in ancient coinage

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