The coinage reform of Augustus refers to the reform of

Roman currency Roman currency for most of Roman history consisted of gold, silver, bronze, orichalcum#Numismatics, orichalcum and copper coinage. From its introduction during the Roman Republic, Republic, in the third century BC, through Roman Empire, Imperial ...

undertaken by

Augustus Gaius Julius Caesar Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian (), was the founder of the Roman Empire, who reigned as the first Roman emperor from 27 BC until his death in A ...

in 23 BC.

The reform

Augustus brought the minting of

gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...

and

silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...

coins, the ''

aureus The ''aureus'' ( ''aurei'', 'golden') was the main gold coin of ancient Rome from the 1st century BC to the early 4th century AD, when it was replaced by the ''solidus (coin), solidus''. This type of coin was sporadically issued during the Roman ...

'' and

denarius The ''denarius'' (; : ''dēnāriī'', ) was the standard Ancient Rome, Roman silver coin from its introduction in the Second Punic War to the reign of Gordian III (AD 238–244), when it was gradually replaced by the ''antoninianus''. It cont ...

, under his personal control while it is thought he left the minting of bronze coinage under senatorial control. Throughout these reforms, Augustus did not alter the coins' weight or

fineness The fineness of a precious metal object (coin, bar, jewelry, etc.) represents the weight of ''fine metal'' therein, in proportion to the total weight which includes alloying base metals and any impurities. Alloy metals are added to increase hard ...

. The gold ''aureus'', weighing about one-quarter

ounce The ounce () is any of several different units of mass, weight, or volume and is derived almost unchanged from the , an Ancient Roman unit of measurement. The avoirdupois ounce (exactly ) is avoirdupois pound; this is the United States ...

, was worth twenty-five silver denarii, weighing about one-eighth of a troy ounce. Augustus more comprehensively reformed denominations below the denarius. New ratios were fixed among the currencies: the

sestertius The ''sestertius'' (: ''sestertii'') or sesterce (: sesterces) was an Ancient Rome, ancient Roman Roman currency, coin. During the Roman Republic it was a small, silver coin issued only on rare occasions. During the Roman Empire it was a large ...

was now minted from about an ounce of

orichalcum Orichalcum (or aurichalcum) or orichalc is a metal mentioned in several ancient writings, including the story of Atlantis in the ''Critias'' of Plato. Within the dialogue, Critias (460–403 BC) says that orichalcum had been considered second ...

, an alloy of

copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...

and

zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...

, rather than silver, and fixed at a quarter of a

. The

dupondius The ''dupondius'' (Latin ''two-pounder'') was a brass coin used during the Roman Republic and Roman Empire valued at 2 '' asses'' (4/5 of a ''sestertius'' or 1/5 of a ''denarius'' during the Republic and 1/2 of a ''sestertius'' or 1/8 of a ''de ...

, formerly a two-

pound Pound or Pounds may refer to: Units * Pound (currency), various units of currency * Pound sterling, the official currency of the United Kingdom * Pound (mass), a unit of mass * Pound (force), a unit of force * Rail pound, in rail profile * A bas ...

bronze Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloid ...

coin, was now

, valued at half a sestertius and weighing half as much. The half-ounce '' as'', worth half a dupondius, the

semis The ''semis'' () was a small Roman bronze coin that was valued at half an '' as''. During the Roman Republic, the ''semis'' was distinguished by an 'S' (indicating ''semis'') or 6 dots (indicating a theoretical weight of 6 '' unciae''). Some ...

, worth half an ''as'', and the

quadrans The ''quadrans'' () or ''teruncius'' () 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, showing three pellets representing thre ...

, worth half a semis, were the first pure copper coins minted in Rome since 84 BC.

References

23 BC 20s BC in the Roman Empire Coins of ancient Rome Augustus {{AncientRome-stub