One day I found this engraved gem in some dark shop in an old town... I did not know if it was ancient or not but, because I liked it and it was not expensive, I bought it. It represents a late Roman or early Byzantine emperor with the legend ROMVLVS MOMILVS. Of course there is no emperor of that name. The last western Roman emperor was the young Romulus Augustus, nicknamed Augustulus ("the little Augustus") according to ancient authors like Jordanes or the Anonymus Valesianus. Solidi were minted in Ravenna with his name : DN ROMVLVS AVGVSTVS PF AVG. He was deposed on 9/4/476 and this day was the last day of Antiquity : the next morning was the first day of the Middle Ages - but nobody noticed. In the 16th c. Hubert Goltzius, one of the very first people to ever write a book on ancient coins, listed all Roman emperors coin legends. He could not check all collections by himself and often relied on descriptions sent by correspondents. One of his correspondents was not very good at deciphering coin-legends, this is why Goltzius listed Romulus Augustulus' coin legends this way: Fl. Momyl. Augustulus? Reading this, Adolf Occo, another numismatist of the same period, thought that this emperor's name must have been "Flavius Momyllius Augustulus". This was not what was written on the coins he had in hand, but he trusted Goltzius more than his own eyes and copied in his own book : MOMVLVS AVGVSTVS or MOMVLVS AVGVSTVL... Such was the authority of these pioneers that nearly all historians from the 16th to 18th c. wrote that the last Western emperor was called Momylus or Momillus. Some explained this, saying it was another nickname, from the Greek momos, disgrace : Momyllus meant "little disgrace". The German engraver Christian Wermuth created a "Momillus" medal and included it in his 1694 collection of medals of the great emperors of History : In his Decline and Fall Edward Gibbon writes : "The son of Orestes assumed and disgraced the names of Romulus Augustus; but the first was corrupted into Momylus, by the Greeks, and the second has been changed by the Latins into the contemptible diminutive Augustulus." (chap. XXXVI) Inspired by Wermuth's medal, an unknown artist, probably in the 18th or early 19th c., forged the last emperor's gem seal. One of these gems, allegedly found in Rome, was declared authentic by the then famous expert Henri Hoffmann and auctioned in Paris in 1888. Of course, some numismatists since the 17th c. had said that this emperor's name on coin legends was Romulus Augustus and nothing else, that Goltzius and Occo had forged monstrosities, but their opinion did not prevail until the late 19th c. And we are not completely rid of "Momylus": this nickname that never existed is still on Romulus Augustulus' Wikipedia page. Sometimes, I wonder if the seal of Alaric II, which is in Vienna Kunsthistorisches Museum and has been in the Habsburgs collections since only... 1784, is actually authentic, and not the work of the same forger as my gem .
I would not call such an item a fake since it was not a copy of an ancient object but an original work of modern scholarship (or lack thereof). It is rather like the Paduan medals that are not copies of real sestertii. See: https://coinsweekly.com/creator-of-the-paduans-giovanni-da-cavino/
To me, forgery implies an intent to deceive by the maker. What do you call replicas made for study or new works inspired by the spirit of an older work? Are artists today who paint in a pointillist style forging Seurat or one of the other impressionists who pioneered the method? To me the difference comes when the creator of a work tells people that it is something it is not. A Slavey, Antiquanova, Westair or British Museum electrotype replica can be sold by a fraudulent or ignorant person but that does not make 'forgers' out of their creators. We need a word for things made to honor rather than deceive.
I understand your point but nothing tells me this intaglio was not made to deceive. Consider the other Momillus gem (obviously made by the same engraver) that was auctioned in 1888 : it did deceive. The expert, Henri Hoffmann, states it is authentic, because he knows very well many other experts will doubt its authenticity - Ernest Babelon wrote he doubted much. This is also why I doubt the authenticity of the seal of Alaric which is in Vienna: it looks too much like my gem and, even more, another seal of Alaric has just been published (Genevra Kornbluth, 'A Second Seal of Alaric, Rex Gothorum', in Gemmae, an international journal on glyptic studies I (2019), Pisa-Roma (Fabrizio Serra), p. 105-126). Kornbluth concludes that both are authentic !