Constantius II, 337-361. Solidus (Gold, 21 mm, 4.37 g, 1 h), Sirmium, September 351-6 November 355. FL IVL CONSTAN-TIVS PERP AVG Pearl-diademed, helmeted and cuirassed bust of Constantius II facing, his head turned slightly to right, holding a spear in his right hand and with a shield decorated with a horseman to left over his left shoulder; to right, small collector's mark: dolphin swimming left, embracing small A with its tail and with an I to upper left, all within incuse punch. Rev. GLORIA REI PVBLICAE / ✱SIRM✱ Roma, helmeted, seated facing on the left, and Constantinopolis, turreted, seated to left with her right foot on prow on the right, holding between them a shield inscribed VOT / XXX / MVLT / XXXX. Depeyrot 6/1. RIC 8. An attractive piece with a charming and very interesting collector's mark on the obverse. Light die break on the obverse and struck from a slightly worn reverse die, otherwise, nearly extremely fine.
The miniscule and carefully executed collector's mark on the obverse immediately recalls the famous silver eagle marks from the Renaissance collection of the Gonzaga family, the rulers of Mantua. The style and fabric of the mark, however, point to sometime later, possibly the 18th or 19th century. Unfortunately, the identification of the previous owner is seriously hampered by the fact that the dolphin was used in various coats of arms - most prominently in those of the dauphins of France - and the letters I and A do not provide much information either. It certainly is, though, a very interesting and highly unusual piece and well worthy of further study by a passionate heraldist.

We have been informed that the punch mark is of Serbian origin and dates to the late 1800s, when it was applied to approve the fineness of gold coins