Rome! It is amazing to me that one word can evoke so many images. The Eternal City doesn't come by its name by accident. A city that was little more than a market place in the fifth century B.C. came to dominate the world for a millennia, and our imaginations to the present.
The emperors of Rome were the dominant movers of the political arena of the ancient world. To take one to write about is for me truly difficult, as each emperor didn't arise from a vacuum. The connections of one to another are too profound and intertwined.
If I must isolate one individual to address, Diocletian to me is a prime candidate. He seems to me a bridge from the very old to the very new, almost early modern. Beginning with Claudius II Gothicus in 268 A.D. and ending with the death of Numerian in 284 A.D. when Diocletian becomes emperor, there were a total of nine emperors. Not bad for sixteen year period.
The job confronting Diocletian was prodigious. His first task was to put to death the person that killed Numerian. A certain Arrius Aper, a praetorian prefect, killed Numerian in hopes of being selected as the next emperor. The troops didn't buy it and selected Diocletian instead. Diocletian then quite swiftly disposed of Aper. Diocletian's trip to the purple, as with many of his predecessors, was through the military. Born in Dalmatia (present day Yugoslavia,-- or what's left of it), the son of a poor family, he rose through the military heirarchy until Numerian made him commander of the officer cadet corps attached to the imperial staff. It was in this way he was in position to avenge Numerian's death while on an expedition against the Persians.
In 284 A.D. the empire was vast, stretching from Britain to the Black Sea. It soon became apparent to Diocletian that the job was too big for one man, and after consolidating his position in Europe, he appointed Maximian as Caesar and later as full partner as Augustus in 286 A.D. While this concept of dual rulers wasn't new, it was meant to be permanent. The system underwent change again in 293 A.D. when Constantius I and Galerius were appointed as Caesars creating the tetrarchy and a boon to present day numismatists, as these individuals all had coinage of one type or another struck in mints from Londinium to Antioch.
It is one thing to be an emperor, another to stay in control. Diocletian was a brilliant manager and soldier. To keep the empire viable, a strong economy was needed. People need food, soldiers need pay. It is generally accepted that the great coinage reform of Diocletian was initiated in 294 A.D. as there were no antoniniani issued after that date. Pre-reform antoniniani with C and D officiane from Trier were produced with the vota X. Also, their styles reflected the earlier antoniniani. The reformed folles bearing the officinal letters C and D now start to appear from Trier along with unmarked silver of the same style. Production of the washed antoninani disappear and the arrival of new silver coins and a range of new bronzes make their appearance.
Sixteen mints operated in this period reflecting the administrative and political changes in the empire. They were Londinium, Treveri, Lugdunum, Ticinum, Aquileia, Roma, Ostia, Carthago, Siscia, Serdica, Thessalonica, Heraclea, Nicomedia, Cyzicus, Antiochia, and Alexandria. Aquila, Thessalonica, and Nicomedia came into being with the reform. Serdica, Carthago, and Ostia were also tied to the reform though came into being later. It is interesting to note that Diocletian was always the senior Augustus. His use of Jovius, son of Jupiter, on his coins reflects this, while Maximian used Herculius, who was lower in rank, shows the deference paid to the senior Augustus. This was not lost on the populace.
A brief not on the reason the tetrarchy was necessary. This size of the empire was such that it needed superb military and managerial skills. There was great pressure on the frontiers and Maximian performed his military job well. But by 290 A.D. it was obvious that the dyarchy couldn't do it all. Hence Constantius I and Gelarius Maximian came into the picture as Caesars, and therefore junior to the augusti. The two brothers, Jovians and Herculians were the true powers even though the Caesars were brought into the imperial house. Each emperor exercised military and administrative rights in their own spheres. This includes mints and mints followed by soldiers and conquest. It was also during this time that Egypt's currency was unified with the rest of the empire.
As nearly as can be deduced, the relative values and denominations of Diocletian's reformed coinage are as follows:
|1 AV aureus||=||24 AR argentei|
|1 AR argenteus||=||5 AE folles|
|1 AE follis||=||5 AE denarii|
|1 AE antoninianus||=||1 post-reform radiate||=||2 AE denarii|
The gold aureus was struck at 60 to the pound at 12 grains. This was an increase in weight from the pre-reform 70. A new silver coin, probably called the argentius was about the same weight and fineness as Nero's denarius. A new bronze coin also came into being. This follis was about equal in size and weight as the old as of earlier times and was silver washed. There were coins similar to the earlier antoniniani struck with no trace of silver as the earlier ones had about 4%. It is suspected that the transference of the number XXI to the follis from the old antoniniani gave the follis the 20 parts copper to 1 part silver as was found on the antoniniani of Aurelian.
As faces changed in the tetrarchy, new designs appeared. As normal in Roman coinage, devices were chosen to reflect the political and economic realities. As Severus and Constantine I came in as Caesars, designs reflecting their ties to the gods were reflected. Constantine's Sol Invictus devices are well known. Constantine I the Great was one of the tetrarchs; he is the bridge from the old to the new. Under him, the young Christian Church was allowed to thrive and prosper. Under him, we see the seeds of the medieval era beginning to be sown. The coinage of Constantine and his sons start to take on the distinct Byzantine style. Under him, the new Rome, Constantinople, is built.
The coinage of this time period is prodigious. It is certainly beyond the scope of this paper to identify the outputs by mint, type, and metal. I hope this whets the appetite of the reader to further pursue this interesting era of imperial coinage.
The Roman Emperors, A Bibliographical Guide to the Rulers of Imperial Rome, 31 B.C. - 476 A.D. Michael Grant. Charles Scribner's Sons. New York, New York, 1985.
Roman Coins and Their Values. David R. Sear. Fourth Revised Edition. B.A. Seaby Ltd.
The Roman Imperial Coinage, Volume VI, from Diocletian's Reform (A.D. 294) to the Death of Maximinus (A.D. 313). C.H.V. Sutherland. Edited by C.H.V. Sutherland M.A., D. Litt., F.S.A., and R.A.G. Carson, M.A., F.S.A. London. Spink and Son Ltd. Reprinted 1984.