When one reviews the listing of the coins of Severus Alexander on my introduction of Severus Alexander page or various references, the antoninianus will be missing. Is this a mistake? Do they exist? The answer is yes they do exist, but with a large explanation of how.
How can they exist when noted scholars such as Sear in Roman Silver Coins Volume III that "the antoninianus (double denarius) was not struck under this reign, and was not re-introduced until the joint reign of Balbinus and Pupienus, 238 A.D"? Am I saying that Sear made a mistake? No, Sear is correct. No legitimate double-denarius of Severus Alexander were minted during his reign. The Antoninianus or double denarius was actually not double the weight of a regular denarius, but actually less than double. It was a way to manipulate coinage to save on silver and in affect cheat the public. As such a blatant attack on the money system, Severus Alexander stopped it from being minted during his reign. Although he did not allow them to be produced during his reign, double-denarius of Severus Alexander do exist. There are two different sources of these coins.
First, there are two different modern forgeries of the double-denarius of Severus Alexander noted on my my introduction to Severus Alexander page. I will not spend any time on forgeries.
The second and more important authentic antoninianus of Severus Alexander were not minted in his time but were done as tributes to him by the Emperor Trajan Decius in 250-251 AD. There were two different styles to the coin, one with two different reverses:
Roman Silver Coins (RSC) #597
Roman Siver Coins (RSC) #598.
Roman Siver Coins (RSC) #598.
Roman Siver Coins (RSC) #598.
Roman Silver Coins (RSC) #599.
The first coin, RSC 597, has the legend DIVO ALEXANDRO on the obverse with a radiant bust and the reverse's legend is CONSECRATIO depicting a lighted altar with two palmettes.
The second and third coins, RSC 598, are identical except on the reverse it does not have the two palmettes on the ends of the altar.
The fourth and fifth coin, RSC 599, has the same legends and obverse, with the reverse having a standing eagle looking left.
For a great discussion and listing of the "divi" series of Trajan Decius, see David Vagi's Coinage and History of the Roman Empire Volume II: Coinage pages 428-429.
