In 1755 Richard Mead M.D. owned an aureus of the type we now refer to as RRC 506/1.
The above engraving is intriguing because it does not seem to fill in missing detail. The engraver seems to be trying for high degree of accuracy, not just here but on the other plates. The missing tie on the bottom of what is here shown as the reverse (the PRIM side) is on the key clues. It rules out a match with many known specimens. The only possible matches are on the below list are 6 and 9, but I don’t think either is a perfect match.
A mystery where the Mead specimen is today.
At last count 9 specimens were known. I quote and annotate:
A revised census of the specimens we can account for and based on Bahrfeldt’s original list (compiled with the aid of Michel Amandry, Hadrien Rambach, and Alan Walker):
1). BMCRR East 57 = Duke of Devonshire Collection = Henry Platt Hall Collection = Leo Biaggi de Blasys Collection = Ratto Stock = Present location unknown? [image below]
2). Hunterian Collection (Glasgow) [image below]
3). Münzkabinett Berlin = Marquis Lionel René de Moustier Collection (Hoffmann, 1872), lot 42
4). Kunsthistorisches Museum Wien [Vienna] (plated in Bahrfeldt) [Non vide]
5.) BMCRR East 58 = Dupré-Wigan Collection [image below]
6). Duplicate from the Bibliothèque Nationale, purchased in 1844 from the Paris dealers Charles-Louis Rollin (1777-1853) and his son Claude-Camille Rollin (1813-1883) = Münzen und Medaillen AG 77 (18 September 1992), lot 141 = RBW Collection (Triton III, 30 November 1999), lot 844 = Property of an European Nobleman (Numismatica Ars Classica 24, 5 December 2002), lot 6
7). Vatican Collection (Rome) [Non vide]
8). Ponton d’Amécourt (Rollin & Feuardent, 25 April 1887), lot 26. Present location unknown? [Non vide]
9.) Bibliothèque Nationale (Paris) = Montagu (Rollin & Feuardent, 20 April 1896), lot 40 = Comte du Chastel Collection (Rollin & Feuardent, 27 May 1889), lot 179.