About Roman Coins
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A very brief summary is given below
Roman coins have survived over 1,500 years in surprisingly large numbers and are relatively inexpensive.
The ‘heads’ side (obverse) of a Roman coin normally bears a portrait of the Emperor or of his son or junior emperor with their names and titles and occasionally of the Emperor's wife (Avgvsta). First and second century coins are renowned for the quality of their portraits.
The ‘tails’ side (reverse) was used to give out a message, proclaiming the Emperor’s virtues and achievements through various symbolic or more direct images. These include gods and goddesses (Mars, Mercury, Jupiter, etc), personifications of virtues (Peace, Fortune, etc.), military symbols (soldiers, standards, camp gates, etc.), personifications of countries (e.g . Britannia), even animals (including the she-wolf with Romulus and Remus).
Coin Types - 1st to 3rd centuries AD
The smallest coin was the copper QUADRANS. A quadrans was the Widow's Mite of the Bible.
A brass SEMIS was worth two quadrantes.
The next coin was a copper AS (c 25 mm) which was worth four copper quadrantes.
A brass DUPONDIUS (the same size as the as) was worth two asi. Usually the Emperor was shown wearing a radiate crown on this coin (instead of a laurel wreath) to help distinguish it from the similar sized As
A brass SESTERTIUS (30-35 mm) was worth two dupondii. The sestertius was the denomination the romans used to express large values - e.g. land or property values. When the Senate offered the Imperial Crown to the highest bidder, the winning bid was for 25,000 sestertii for each senator.
Many copper and 'brass' coins turn an even shade of green over a long period of time (hundreds of years). This is known as a patina and, as it cannot be forged, is considered attractive and desirable. Never be tempted to clean such coins.
A silver DENARIUS (17-18 mm) was worth 4 sestertii, 8 dupondii or 16 asi.
A legionary soldier was paid 300 denarii and a centurion was paid 3000 denarii a year but half of this was kept back as payment for food and clothing, so a denarius was probably the equivalent of a £20 note in today’s money and a sestertius about £5.
Later on, as inflation began to bite, a silver ANTONINIANUS was issued - in value a double denarius but it only contained 1½ as much silver! Antoniniani are distinguished by the radiate crown on the Emperor's portrait (instead of the normal laurel wreath). For Empresses, the symbol was a crescent behind the neck.
A gold AUREUS was worth 25 denarii
Inscriptions on the coins
The following are the most common inscriptions on the obverse (heads) side, the titles being often abbreviated, IMP for Imperator, AVG for Augustus, COS for Consul, TR P for Tribunica Potestas, etc
The Emperors titles always include Imperator (= Commander-in-Chief), the most important title and Augustus (roughly meaning Emperor - after the first Emperor). They might also include some or all of the following: Caesar (the title later given to the Emperor's son or heir), Pontifex Maximus (Head Priest), Tribunica Potestas * (Tribunal Power - protector of the people), Consul *(Chief Magistrate), Pater Patriae (Father of his Country). The two titles starred were renewed from time to time and are often followed by a number which is a help to dating. The lesser titles can appear on either side of the coins. DIVUS (male) or DIVA (female) before the name indicates that the coin is a commemorative, issued after his/her death.
Coin Types - 3rd and 4th centuries AD
This was a time of increasing inflation as the government had to mint more and more money to pay the soldiers of a larger and larger army needed to defend the Empire's frontiers.
In the third century, Antoniniani were still issued but contained less and less silver until they were made of bronze with a wash of silver. Smaller bronze coins were also issued. In the later 3rd and 4th centuries various attempts were made to reform the coinage and new types of coins were issued. Their names and values are not always clear but the reverse (tails side) often have interesting designs. Modern coin dealers classify them by size AE1 (the largest) to AE 4 (the smallest).
Inscriptions on the coins
Whereas Imperator (= Commander-in-Chief) was the most important title for the early Emperors, this was gradually replaced by Dominus Noster (= our lord) which was normally abbreviated to D.N. from the early 4th century. Emperors who adopted this form, usually also included P.F. after their names (Pius Felix = Dutiful and Fortunate. Augustus (abbreviated to AVG) was reserved for the senior Emperor and where the Empire was divided into spheres of influence, e.g. East and West, the use of an extra G indicated this AVGG. The plural of DN was DD NN. Caesar remained the title for the Emperor's heir or junior Emperor and is usually shown in the form NOB CAES (Noblissimus Caesar = Noblest Caesar) - plural CAESS.