Julius Caesar struck the coin more often, and standardized the weight at one-fortieth of a Roman pound, about 8 grams. Octavian Augustus tariffed the value of the
sestertius as one-hundredth of an
aureus. The
aureus, which mint was placed at
Lugdunum, weighed of a pound (7.79 grams) and was worth 25
denarii and 100
sestertii. A sub-multiple existed, the gold
quinarius or half-
aureus. The Augustan system of the 1st century was as follows: The mass of the
aureus was decreased to of a Roman pound (7.3 g) during the reign of
Nero (). According to
Cassius Dio, writing at the start of the 3rd century, notes that the
aureus was still worth 100
sesterii, and comments that it was equivalent to 20 Greek
drachmas. At about the same time the purity of the silver coinage was also slightly decreased. , After the reign of
Marcus Aurelius (r. 161–180) the production of
aurei decreased, and the weight fell to one-fiftieth of a Roman pound (6.5 g) by the time of
Caracalla (). During the 3rd century, the Roman Empire experienced a
50-year period of instability that also saw an increasingly severe economic and monetary crisis. The number and weight of
aurei produced decreased more and more rapidly, dropping from about 7.20 grams under
Septimius Severus () to less than 3.50 grams under
Valerian (), about half of its original value. The simultaneous devaluation of gold and silver coins caused their mutual devaluation. While the correspondence of 25 denarii for 1
aureus was maintained during the 1st and 2nd centuries, the value of the
aureus became unstable: a Greek inscription under the reign of
Philip () gives 1
aureus for 21
antoninianii, or 42
denarii. Under
Gallienus(), the purity was briefly reduced to 94%, and a small amount of coins were minted with as low as 80% purity. This was reset back to 99% by the next emperor. In that same year, Diocletian issued the
Edict on Maximum Prices fixing a price for minted gold of 72,000
denarii per pound, or more than a thousand
denarii for one
aureus, the denarius being no more than a unit of account. This authoritarian measure did nothing but stop the fluctuation of the
aureus. Diocletian's
solidus was struck only in small quantities, and thus had only minimal economic effect, although its stable weight brought an end to the instability that had existed for a while. When the
solidus was reintroduced by
Constantine I (r. 306–337) in 312 AD, permanently replacing the
aureus as the gold coin of the Roman Empire, it was struck at a rate of 72 to a Roman pound of pure gold, each coin weighing twenty-four Greco-Roman
carats, or about 4.5 grams of gold per coin. By this time, the
solidus was worth 275,000 of the increasingly debased
denarii. However, regardless of the size or weight of the
aureus, the coin's purity was little affected. Due to runaway inflation caused by the Roman government's issuing base-metal coinage but refusing to accept anything other than silver or gold for tax payments, the value of the gold
aureus in relation to the
denarius grew drastically. Inflation was also affected by the systematic debasement of the silver
denarius, which by the mid-3rd century had practically no silver left in it. Today, the
aureus is highly sought after by collectors because of its purity and value, as well its historical interest. An
aureus is usually much more expensive than a
denarius issued by the same emperor. For instance, in one auction, an
aureus of
Trajan (r. 98–117) sold for $15,000, and a silver coin of the same emperor sold for $100. The most expensive
aureus ever sold was one issued in 42 BC by
Marcus Junius Brutus, the assassin of
Gaius Julius Caesar, which had a price realized of $3.5 million in November 2020; there is an example of this coin on permanent display at the
British Museum in London. An
aureus, issued by the emperor
Alexander Severus (r. 222–235), has a picture of the
Colosseum on the reverse, and had a price realized of $920,000 in 2008. An
aureus with the face of
Allectus was auctioned off in the United Kingdom for £552,000 in June 2019. File:Gold Aureus of Augustus (obverse).png|1.
Augustus File:Gold aureus of Tiberius.jpg|2.
Tiberius File:Caligula&Germanicus Aureus (obverse).jpg|3.
Caligula File:Aureus of Claudius (obverse).jpeg|4.
Claudius File:Gold Aureus of Nero.png|5.
Nero File:Galba, aureus (obverse).jpg|6.
Galba File:Gold Aureus of Otho.jpg|7.
Otho File:Vitellius, aureus, 69, RIC I 85 (obverse).jpg|8.
Vitellius File:INC-2056-a Ауреус. Веспасиан. Ок. 75—79 гг. (аверс).png|9.
Vespasian File:Rare aureus of Titus (obverse).jpg|10.
Titus File:INC-1882-a Ауреус. Домициан. Ок. 87 г. (аверс).png|11.
Domitian File:Nerva aureus (obverse).png|12.
Nerva File:TRAJAN RIC II 257 (obverse).png|13.
Trajan File:Hadrian RIC II 308 (obverse).jpg|14.
Hadrian File:INC-1833-a Ауреус Антонин Пий ок. 153-154 гг. (аверс).png|15.
Antoninus File:INC-1817-a Ауреус Марк Аврелий ок. 166-167 гг. (аверс).png|16.
Marcus File:INC-2957-a Ауреус. Луций Вер. Ок. 163—164 гг. (аверс).png|17.
Lucius File:INC-1818-a Ауреус Коммод ок. 186-187 гг. (аверс).png|18.
Commodus File:Aureus of Pertinax (obverse).jpg|19.
Pertinax File:Aureus Didius Iulianus (obverse).jpg|20.
Julianus File:Septimius Severus. AD 193-211 (obverse).jpg|21.
Severus File:Caracalla RIC 4A-211b (obverse).jpg|22.
Caracalla File:Rare aureus of Geta (obverse).jpg|23.
Geta File:Aureus Macrinus-RIC 0079 (cropped).jpg|24.
Macrinus File:INC-1854-a Ауреус Элагабал ок. 218-219 гг. (аверс).png|25.
Elagabalus File:INC-1855-a Ауреус Север Александр ок. 228 г. (аверс).png|26.
Alexander ==See also==