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Collecting Roman Coins - The Sestertius
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The History of Roman Coins - The Sestertius

The sestertius, or sesterce, was an ancient Roman coin. During the Roman Republic it was a small, silver coin issued only on rare occasions. During the Roman Empire it was a large brass coin.

The name sestertius (originally semis-tertius) means '2 �', the coin's original value in asses, and is a combination of semis 'half' and tertius 'third', that is, 'the third half' (0 � being the first half and 1 � the second half) or 'half the third' (two units plus half the third unit, or halfway between the second unit and the third). Parallel constructions exist in Danish with halvanden (1 �), halvtredje (2 �) and halvfjerde (3 �). The form sesterce, derived from French, was once used in preference to the Latin form, but is now considered old-fashioned.


The sestertius was introduced ca. 211 BC as a small silver coin valued at one-quarter of a denarius (and thus one hundredth of an aureus). A silver denarius was supposed to weigh about 4.5 grammes, valued at ten asses, with the silver sestertius valued at two and one-half asses. In practice, the coins were usually underweight.

When the denarius was re-tariffed to sixteen asses (due to the gradual reduction in the size of bronze denominations), the sestertius was accordingly revalued to four asses, still equal to one quarter of a denarius. It was produced sporadically, far less often than the denarius, through 44 BC.

In or about 23 BC, with the coinage reform of Augustus, the denomination of sestertius was introduced as the large brass denomination. The sestertius was produced as the largest brass denomination until the late third century AD. Most were struck in the mint of Rome but from AD 64 during the reign of Nero (AD54- 68) and Vespasian (AD69- 79), the mint of Lyon (Lugdunum), supplemented production. Lyon sestertii can be recognised by a small globe, or legend stop), beneath the bust.

The brass sestertius typically weighs in the region of 25 to 28 grammes, is around 32-34 mm in diameter and about 4mm thick. The distinction between bronze and brass was important to the Romans. Their name for brass was orichalcum, a word sometimes also spelled aurichalcum (echoing the word for a gold coin, aureus), meaning 'gold-copper', because of its shiny, gold-like appearance when the coins were newly-struck (see, for example Pliny the Elder in his Natural History Book 34.4).

Orichalcum was considered, by weight, to be worth about double that of bronze. This is why the half-sestertius, the dupondius, was around the same size and weight as the bronze as, but was worth two asses.

Sestertii continued to be struck until the late third century there was a marked deterioration in the quality of the metal used and the striking even though portraiture remained strong. Later emperors increasingly relied on melting down older sestertii, a process which led to the zinc component being gradually lost as it burned off in the high temperatures needed to melt copper (Zinc melts at 419 �C, Copper at 1085 �C). The shortfall was made up with bronze and even lead. Later sestertii tend to be darker in appearance as a result and are made from more crudely prepared blanks.

The gradual impact of inflation caused by debasement of the silver currency meant that the purchasing power of the sestertius and smaller denominations like the dupondius and as was steadily reduced. In the first century AD, everyday small change was dominated by the dupondius and as, but in the second century, as inflation bit, the sestertius became the dominant small change. In the third century silver coinage contained less and less silver, and more and more copper or bronze. By the 260s and 270s the main unit was the double-denarius, the antoninianus, but by then these small coins were almost all bronze. Although these coins were theoretically worth eight sestertii, the average sestertius was worth far more in plain terms of the metal they contained.

Some of the last sestertii were struck by Aurelian (270- 275 AD). During the end of its issue, when sestertii were reduced in size and quality, the double sestertius was issued first by Trajan Decius (249- 251 AD) and later in large quantity by the ruler of a breakaway regime in the West called Postumus (259- 268 AD), who often used worn old sestertii to overstrike his image and legends on. The double sestertius was distinguished from the sestertius by the radiate crown worn by the emperor, a device used to distinguish the dupondius from the as and the antoninianus from the denarius.

Eventually, the inevitable happened. Many sestertii were withdrawn by the state and by forgers, to melt down to make the debased antoninianus, which made inflation worse. In the coinage reforms of the fourth century AD, the sestertius played no part and passed into history.

As a unit of account

The sestertius was also used as a standard unit of account, represented on inscriptions with the monogram HS. Large values were recorded in terms of sestertium milia, thousands of sestertii, with the milia often omitted and implied. The hyper-wealthy general and politician of the late Roman Republic, Crassus (who fought in the war to defeat Spartacus), was said by Pliny the Elder to have had 'estates worth 200 million sesterces'.

A loaf of bread cost roughly half a sestertius, and a sextarius (~0.5 liter) of wine anywhere from less than half to more than 1 sestertius. One modius (6.67 kg) of wheat in 79 AD Pompeii cost 7 sestertii, of rye 3 sestertii, a bucket 2 sestertii, a tunic 15 sestertii, a donkey 500 sestertii.[1]

Records from Pompeii show a slave being sold at auction for 6,252 sestertii. A writing tablet from Londinium (Roman London), dated to c. 75- 125 AD, records the sale of a Gallic slave girl called Fortunata for 600 denarii, equal to 2,400 sestertii, to a man called Vegetus. It is difficult to make any comparisons with modern coinage or prices, but for most of the first century AD the ordinary legionary was paid 900 sestertii per annum, rising to 1,200 under Domitian (81-96 AD), the equivalent of 3.3 sestertii per day. Half of this was deducted for living costs, leaving the soldier (if he was lucky enough actually to get paid) with about 1.65 sestertii per day.

The Democratic Republic of the Congo has one of the lowest purchasing power parities per capita in the modern world, about $300 or �350 according to the World Bank and the International Monetary Fund. With its technological advantage offset by instability and civil war, its economy is comparable to that of the ancient world and can be used to give a rough estimate of the modern equivalent of the value of a sestertius in ancient Rome.

If we assume a legionary's wages were based on an individual who needed to support a family of 5 with a working wife, a typical yearly income for the family could be around 1,000 sestertii. This would correspond to between $1500 and $1750 per year for a family of five in Congo, although other factors such as income inequality and the citizen status of legionaries mean this figure is not perfectly accurate. It could be assumed though that at one point 1 sestertius was the equivalent of $1.50, 1.11 euros or �1. According to this exchange rate a Congo citizen living on $150 a year could afford 400 pounds of bread a year in ancient Rome, which is enough to keep someone healthy enough to work, a standard of living common to Roman plebeians and slaves of the time.

Numismatic value

Sestertii are highly valued by numismatists, since their large size gave caelatores (engravers) a large area in which to produce detailed portraits and reverse types. The most celebrated are those produced for Nero (54-68 AD) between the years 64 and 68 AD, created by some of the most accomplished coin engravers in history. The brutally realistic portraits of this emperor, and the elegant reverse designs, greatly impressed and influenced the artists of the Renaissance. The series issued by Hadrian (117-138 AD), recording his travels around the Roman Empire, brilliantly depicts the Empire at its height, and included the first representation on a coin of the figure of Britannia; it was revived by Charles II, and was a feature of United Kingdom coinage until the 2008 redesign.

Very high quality examples can sell for over a million dollars at auction as of 2008, but the coins were produced in such colossal abundance that millions survive. Worn, but recognisable, examples of common types can be found for as little �10 or $20.
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